On your Remote Storage Settings page, choose Google Drive Backup.
It will ask you to sign into – and confirm the password – of your google account you want to use for the backup.
As a security measure Google will ask you to permit the access. Allow.
Give it a proper labelling in the Google Drive path so you later know exactly where to find the backup. Especially when creating backups for more then one domain.
And you’re done with the setup. The Remote Storage Settings page will now also show Google Drive as “Ready for use”. 🙂