I believe that you may be looking for this documentation below
If you are building your own login page:
https://fusionauth.io/docs/v1/tech/apis/identity-providers/google#complete-the-google-loginIf you are using the identity providers that ship with FusionAuth on our hosted pages
https://fusionauth.io/docs/v1/tech/identity-providers/googleHope this helps!
Thanks,
Josh
FusionAuth