1. Choose Installed application as your Application type and select Android as the installed application type (these should be your only options).
2. In the Package name field, enter your Android application's package name.
3. Open a terminal and run the Keytool utility to get the SHA1 fingerprint of the certificate. You should get both the release and debug certificate fingerprints.

   To get the release certificate fingerprint:

   keytool -list -keystore <path-to-production-keystore>
   

   To get the debug certificate fingerprint:

   keytool -list -keystore <path-to-debug-keystore>
   

4. The keytool prompts you to enter a password for the keystore. The default password for the debug keystore is android. The keytool then prints the fingerprint to the terminal.
5. Paste the SHA1 fingerprint into the Signing certificate fingerprint (SHA1) field.
6. Click the Create client button, then follow the steps in the Gather credentials for authentication and authorization section below.

For more information about OAuth 2.0 on Android, see Authenticating to OAuth2 Services.

You should create two client IDs, one with the release certificate fingerprint and another with the debug certificate fingerprint. Make sure to use the same package name for both. This allows Google Play games services to recognize calls from your linked APKs that are signed with either certificate. For more information about certificate signing for Android, see Signing Your Application.

You can add more than one Android app to the same game entry in Google Play Console. However, this should only be done if there are different versions of the same game (for example, the free version and the paid version). In this case, always list the paid version before the free version (or the full version before the demo/trial version). Do not link different games to the same project as this may cause incorrect behavior. Instead, create a separate game entry in the Google Play Console for each game that you publish.