How to add google signin to you project?

This section contains information for adding google signin to project. Information for Web, Android and iOS.
If the project does not iOS (iOS app), then steps 3 and 4 can be skipped

If the project does not have a website (web version for users), then steps 5, 6 and 7 can be skipped
1.) You must have a ready-made project in Firebase Console and your project (Android, iOS and web applications) must be configured to work with FCM (Firebase Cloud Messages): https://raccoonsquare.com/help/how_to_create_fcm/
2.) go to Authentication section in you Firebase project (1), select tab "Sign-in method" (2), click "Google" in table (3), click "Enable" (4), click "Save" (5)
How to add google signin to you project?
3.) If project have iOS version, open project in Xcode, select "GoogleService-Info.plist" (1) and copy value "REVERSED_CLIENT_ID" (2)
How to add google signin to you project?
4.) Select project name (1), select "target" (2), select "Info" (3), click "+" button (4) and paste value from "REVERSED_CLIENT_ID" key (from previous step) (5)
How to add google signin to you project?
5.) If project have Website version, go to https://console.cloud.google.com/, select you project (1), click "Credentials" (2), click "Create Credentials" button (3) and select "OAuth client ID" menu item
How to add google signin to you project?
6.) Select application type "Web Application" (1), enter name (2), add you site urls (3,4) and click "Create" (5)
How to add google signin to you project?
7.) copy "Your client Id" (1) and "Your client secret" (2) to constants GOOGLE_CLIENT_ID and GOOGLE_CLIENT_SECRET in db.inc.php config file
How to add google signin to you project?