Create New Project
Go to project
Visit APIs & auth -> Credentials

Click on Create New Client ID
Provide details as given in image

www or https. Then enter// If using www
http://www.yoursite.com
http://www.yoursite.com/auth/google/callback
// If using HTTPS
https://yoursite.com
https://yoursite.com/auth/google/callback
// If using both www and HTTPS
https://www.yoursite.com
https://www.yoursite.com/auth/google/callback
// For subdomains
http://sub.yoursite.com
http://sub.yoursite.com/auth/google/callback

Login to your FTP account
Open .env file
Provide your app id and app secure there.
Save the file.