diff --git a/firestore/CONTRIBUTING.md b/firestore/CONTRIBUTING.md
new file mode 100644
index 0000000000..1adf865d46
--- /dev/null
+++ b/firestore/CONTRIBUTING.md
@@ -0,0 +1,88 @@
+# Overview
+
+This describes how to Firestore CPP SDK works on supported platforms, and how to
+contribute this Firestore CPP SDK.
+
+Please read `README.md` and `CONTRIBUTING.md` from the repository root first.
+
+# Prerequisites
+
+There is no specific prerequisites for Firestore, `README.md` from the root directory
+should have everything you need.
+
+One slight enhancement is to use [https://github.com/pyenv/pyenv][pyenv] to manage
+your python versions, if you work on multiple projects with different python
+requirements.
+
+For CPP SDK to compile, you generally need your `pyenv which python` to point to
+a Python3 installation.
+
+# Architecture
+
+It is easier to work this Firestore CPP SDK by keeping a high level archetecture in mind:
+
+![architecture.png](architecture.png)
+
+To summarize, the C++ Code in this directory is an adapting layer on top of the underlying
+SDKs: Firestore Android SDK for Android, and C++ Core SDK for everything else.
+
+These dependencies live within different github repos, so understanding where and which versions
+of the dependencies being used is critical to troubleshooting, should the issues stem from
+those dependencies or the interop layer.
+
+# Desktop building and testing
+
+Desktop builds of the Firestore SDK uses `CMAKE` to build and test. The complete set
+of tests lives under `${REPO_ROOT}/firestore/integration_test_internal`. To build
+the Firestore CPP SDK and its test suites:
+
+```shell
+# from ${REPO_ROOT}/firestore/integration_test_internal
+mkdir cmake-build-debug
+cd cmake-build-debug
+
+# Generate build files
+cmake .. # Or OPENSSL_ROOT_DIR=${PATH_TO_OPENSSL} cmake ..
+# Build SDK and tests
+cmake --build . -j
+```
+
+Once above steps are successful, there should be a `integration_test` under the current directory:
+```shell
+./integration_test # Run all tests against Firestore Prod Backend
+
+USE_FIRESTORE_EMULATOR=yes ./integration_test # Run all tests against Firestore Emulator
+
+# Run all tests against Firestore Emulator on a custom port
+USE_FIRESTORE_EMULATOR=yes FIRESTORE_EMULATOR_PORT=9999 ./integration_test 
+
+./integration_test --gtest_filter="*Query*" # Run a subset of tests
+```
+
+It is also possible to change where we get the underlying C++ Core SDK living under
+`firebase-ios-sdk` by providing a custom cmake flag `FIRESTORE_DEP_SOURCE`:
+```shell
+# Default behavior when not specified, getting the Core SDK the last C++ SDK release
+# was released with.
+cmake -DFIRESTORE_DEP_SOURCE=RELEASED ..
+
+# Clones the origin/master branch of `firebase-ios-sdk` to get the Core SDK.
+cmake -DFIRESTORE_DEP_SOURCE=TIP ..
+
+# Clones the origin/master branch of `firebase-ios-sdk` to get the Core SDK.
+cmake -DFIRESTORE_DEP_SOURCE=origin/master ..
+
+# Clones commit '555555' of `firebase-ios-sdk`.
+cmake -DFIRESTORE_DEP_SOURCE=555555 ..
+```
+
+## IDE Integration
+
+Open up the repo root directory from `CLion` should load all symbols for the SDK itsel should 
+load all symbols for the SDK itself. Once loaded, you can right load on 
+`firestore/integration_test_internal/CMakeLists.txt` and `load project` to load the tests into
+the IDE.
+
+# Android building and testing
+# iOS building and testing
+
diff --git a/firestore/README.md b/firestore/README.md
deleted file mode 100644
index a99f9ef35b..0000000000
--- a/firestore/README.md
+++ /dev/null
@@ -1,90 +0,0 @@
-# Overview
-
-(TODO: Describe C++ SDK and its scope)
-
-## Integration with FPL
-
-(TODO: Describe how this is integrated with FPL, architecture overview and
-useful commands)
-
-## Copybara process
-
-(TODO: Describe how github C++ code is copied here, what is not copied, and how
-to run the copybara)
-
-## Running integration tests
-
-Given the C++ SDK runs on a lot of platforms, there are many different setups we
-can use to run its integration tests. Below are instructions on how to run them
-with all possible setups.
-
-### Against Firestore emulator
-
-This is the preferred way to run integration tests. The way it is configured is
-we have a controlling `sh_test` (`integration_test_emulator.sh`), which will
-pull Firestore emulator as a `data` dependency and set it up before it finds and
-runs the actual integration tests in separate processes.
-
-Note this means on mobile platforms, the integration tests are run within
-simulation, as there is no way to setup Firestore emulator if they are run on
-real devices.
-
-#### Linux:
-
-```bash
-blaze test //firebase/firestore/client/cpp:cc_emulator_tests
-```
-
-#### iOS (running within iOS simulator on forge-on-mac, hence `darwin_x86_64`):
-
-(TODO: When tests fail, the messages are not properly formatted, especially
-newline is turned into '\n'.)
-
-```bash
-blaze test --config=darwin_x86_64 //firebase/firestore/client/cpp:ios_integration_tests
-```
-
-#### Android (running within Android emulator, requires kvm to run on google3):
-
-(TODO: When tests fail, the messages only tell you the test failed, because of
-the JUnit test wrapping. Ideally we should fix that.)
-
-```bash
-blaze --blazerc=//google/src/head/depot/google3/java/com/google/android/gmscore/blaze/blazerc \
-  test --define=firebase_build=head --config=gmscore_x86 \
-  //firebase/firestore/client/cpp:android_integration_tests \
-  --experimental_one_version_enforcement=warning
-```
-
-Support for other platforms is not available yet.
-
-### Against Firestore prod backend
-
-Running against the actual Firestore backend takes much longer and sometimes our
-tests might get to run in an environment where external network connection is
-impossible (such as Forge).
-
-It is useful still, for example, to run it before a release or to debug issues
-that only happen with real backend.
-
-#### Linux:
-
-```bash
-# Run the tests locally (`--test_output=streamed`) so they have network access.
-blaze test --test_output=streamed //firebase/firestore/client/cpp:cc_tests
-```
-
-#### iOS (Runs on real devices via MobileHarness):
-
-```bash
-blaze test --config=ios_fat --notest_loasd //firebase/firestore/client/cpp:ios_integration_tests_mh
-```
-
-#### Android:
-
-```bash
-blaze --blazerc=//google/src/head/depot/google3/java/com/google/android/gmscore/blaze/blazerc \
-test --define=firebase_build=head --config=gmscore_x86 \
-//firebase/firestore/client/cpp:android_integration_tests_prod \
---experimental_one_version_enforcement=warning
-```
diff --git a/firestore/architecture.png b/firestore/architecture.png
new file mode 100644
index 0000000000..b818babb05
Binary files /dev/null and b/firestore/architecture.png differ
diff --git a/firestore/integration_test_internal/CMakeLists.txt b/firestore/integration_test_internal/CMakeLists.txt
index 75667cb60d..cb3f2e8461 100644
--- a/firestore/integration_test_internal/CMakeLists.txt
+++ b/firestore/integration_test_internal/CMakeLists.txt
@@ -140,6 +140,7 @@ set(FIREBASE_INTEGRATION_TEST_PORTABLE_SUPPORT_SRCS
     src/firestore_integration_test.cc
     src/util/bundle_builder.cc
     src/util/future_test_util.cc
+    src/util/locate_emulator.cc
     src/util/integration_test_util.cc
 )
 
diff --git a/firestore/integration_test_internal/src/firestore_integration_test.cc b/firestore/integration_test_internal/src/firestore_integration_test.cc
index 81f27d7e77..ed6f2df358 100644
--- a/firestore/integration_test_internal/src/firestore_integration_test.cc
+++ b/firestore/integration_test_internal/src/firestore_integration_test.cc
@@ -29,6 +29,7 @@
 #include "android/util_autoid.h"
 #endif  // !defined(__ANDROID__)
 #include "app_framework.h"
+#include "util/locate_emulator.h"
 
 namespace firebase {
 namespace firestore {
@@ -38,37 +39,6 @@ namespace {
 // non-default app to avoid data ending up in the cache before tests run.
 static const char* kBootstrapAppName = "bootstrap";
 
-// Set Firestore up to use Firestore Emulator via USE_FIRESTORE_EMULATOR
-void LocateEmulator(Firestore* db) {
-  // Use emulator as long as this env variable is set, regardless its value.
-  if (std::getenv("USE_FIRESTORE_EMULATOR") == nullptr) {
-    LogDebug("Using Firestore Prod for testing.");
-    return;
-  }
-
-#if defined(__ANDROID__)
-  // Special IP to access the hosting OS from Android Emulator.
-  std::string local_host = "10.0.2.2";
-#else
-  std::string local_host = "localhost";
-#endif  // defined(__ANDROID__)
-
-  // Use FIRESTORE_EMULATOR_PORT if it is set to non empty string,
-  // otherwise use the default port.
-  std::string port = std::getenv("FIRESTORE_EMULATOR_PORT")
-                         ? std::getenv("FIRESTORE_EMULATOR_PORT")
-                         : "8080";
-  std::string address =
-      port.empty() ? (local_host + ":8080") : (local_host + ":" + port);
-
-  LogInfo("Using Firestore Emulator (%s) for testing.", address.c_str());
-  auto settings = db->settings();
-  settings.set_host(address);
-  // Emulator does not support ssl yet.
-  settings.set_ssl_enabled(false);
-  db->set_settings(settings);
-}
-
 }  // namespace
 
 std::string ToFirestoreErrorCodeName(int error_code) {
@@ -163,7 +133,7 @@ Firestore* FirestoreIntegrationTest::TestFirestoreWithProjectId(
   Firestore* db = new Firestore(CreateTestFirestoreInternal(app));
   firestores_[db] = FirestoreInfo(name, std::unique_ptr<Firestore>(db));
 
-  LocateEmulator(db);
+  firestore::LocateEmulator(db);
   return db;
 }
 
diff --git a/firestore/integration_test_internal/src/integration_test.cc b/firestore/integration_test_internal/src/integration_test.cc
index a660c68677..13b36d59f6 100644
--- a/firestore/integration_test_internal/src/integration_test.cc
+++ b/firestore/integration_test_internal/src/integration_test.cc
@@ -43,6 +43,7 @@
 #include "firebase/auth.h"
 #include "firebase/firestore.h"
 #include "firebase_test_framework.h"  // NOLINT
+#include "util/locate_emulator.h"
 
 // The TO_STRING macro is useful for command line defined strings as the quotes
 // get stripped.
@@ -253,6 +254,8 @@ void FirebaseFirestoreBasicTest::InitializeFirestore() {
   ASSERT_EQ(initializer.InitializeLastResult().error(), 0)
       << initializer.InitializeLastResult().error_message();
 
+  LocateEmulator(firestore_);
+
   LogDebug("Successfully initialized Firebase Firestore.");
 
   initialized_ = true;
diff --git a/firestore/integration_test_internal/src/util/locate_emulator.cc b/firestore/integration_test_internal/src/util/locate_emulator.cc
new file mode 100644
index 0000000000..89f7470e1d
--- /dev/null
+++ b/firestore/integration_test_internal/src/util/locate_emulator.cc
@@ -0,0 +1,57 @@
+/*
+ * Copyright 2022 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include "util/locate_emulator.h"
+
+#include <string>
+
+#include "app/src/assert.h"
+
+namespace firebase {
+namespace firestore {
+
+// Set Firestore up to use Firestore Emulator via USE_FIRESTORE_EMULATOR
+void LocateEmulator(Firestore* db) {
+  // Use emulator as long as this env variable is set, regardless its value.
+  if (std::getenv("USE_FIRESTORE_EMULATOR") == nullptr) {
+    LogDebug("Using Firestore Prod for testing.");
+    return;
+  }
+
+#if defined(__ANDROID__)
+  // Special IP to access the hosting OS from Android Emulator.
+  std::string local_host = "10.0.2.2";
+#else
+  std::string local_host = "localhost";
+#endif  // defined(__ANDROID__)
+
+  // Use FIRESTORE_EMULATOR_PORT if it is set to non empty string,
+  // otherwise use the default port.
+  std::string port = std::getenv("FIRESTORE_EMULATOR_PORT")
+                         ? std::getenv("FIRESTORE_EMULATOR_PORT")
+                         : "8080";
+  std::string address =
+      port.empty() ? (local_host + ":8080") : (local_host + ":" + port);
+
+  LogInfo("Using Firestore Emulator (%s) for testing.", address.c_str());
+  auto settings = db->settings();
+  settings.set_host(address);
+  // Emulator does not support ssl yet.
+  settings.set_ssl_enabled(false);
+  db->set_settings(settings);
+}
+
+}  // namespace firestore
+}  // namespace firebase
diff --git a/firestore/integration_test_internal/src/util/locate_emulator.h b/firestore/integration_test_internal/src/util/locate_emulator.h
new file mode 100644
index 0000000000..99225985db
--- /dev/null
+++ b/firestore/integration_test_internal/src/util/locate_emulator.h
@@ -0,0 +1,30 @@
+/*
+ * Copyright 2022 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#ifndef FIREBASE_FIRESTORE_INTEGRATION_TEST_INTERNAL_SRC_UTIL_LOCATE_EMULATOR_H_
+#define FIREBASE_FIRESTORE_INTEGRATION_TEST_INTERNAL_SRC_UTIL_LOCATE_EMULATOR_H_
+
+#include "firestore/src/include/firebase/firestore.h"
+
+namespace firebase {
+namespace firestore {
+
+// Set Firestore up to use Firestore Emulator via USE_FIRESTORE_EMULATOR
+void LocateEmulator(Firestore* db);
+
+}  // namespace firestore
+}  // namespace firebase
+
+#endif  // FIREBASE_FIRESTORE_INTEGRATION_TEST_INTERNAL_SRC_UTIL_LOCATE_EMULATOR_H_