How can I make a user sign in with Google? Please help! 
What have you tried so far? Show your blocks.
Using a webviewer and html/javascript ?
https://firebase.google.com/docs/auth/web/google-signin#web-version-8
This will only get you logged in in the webviewer, you would need to do everything else through the webviewer as well.
If using blocks, you could always try an old school method of testing the entered email address to see if it is a google account address, and just use email/password, but this is not the same as google login...
I don't have any blocks.
Hi there,
The simplest way is to do that with an extension.
https://puravidaapps.com/accountmanager.php
If you don't understand, watch my video: