Google sign-in error, configuration questions. about photos-sharing HOT 1 CLOSED

It sounds like you are trying to set up a different project for use with the codelab and the Google Photos Library API.
If you are running through the codelab, we would recommend creating a new Firebase project dedicated to it and following the steps in the codelab closely to configure your Firebase and signing configuration.
If you are running into any 'duplicate key' issues, you may have to remove the signing certificate/package name combination from any other projects you have configured.

If you want to get started with the Google Photos Library API, you can follow the steps in our developer guide that will walk you through setting up a Google Developers project, enabling the API and configuring sign in: https://developers.google.com/photos/library/guides/get-started

The wizard you have encountered is not useful when you are following the codelab, as you will be using Firebase to handle Google Sign-In and authentication. The credentials are configured in step 4 in the codelab directly in the Firebase console.

If you are setting this up for a different application, you should follow the wizard to configure OAuth access, ("User data"), as you will need authorization from a user. You can find out more about this here: https://developers.google.com/photos/library/guides/authentication-authorization

from photos-sharing.