Go to, https://console.developers.google.com

Create new project Google Console Project

Select console project, Click library and enable Admin SDK library API access

Create OAuth Client ID

Configure authorized re-direct URI's with below callback URL

https://googlegroupsync.ilaesolution.com/google

Click on OAuth Consent Settings and authorize app domain (e.g. googlegroupsync.ilaesolution.com )

Copy client_id and client_secret from created OAuth Client.