1. First login into Google.
3. Create Project.
4. Click on the menu icon on the top left corner and hover your mouse on APIs & Services.
5. Click on library
6. In the library screen, search for "google plus api" and choose the first option and enable it.
8. On the left section of your screen, click on credentials then click on OAuth consent screen tab. Fill in the info and hit save.
9. Click back on credentials and create credentials.6. Choose OAuth Consent Screen and product name which is on the second field.
10. Go back to the credetials screen and click on create credentials and choose OAuth Client ID.
11. Select the web application option and give it a redirect url (at this momment, this is the second option) this way http://yourwebsite.com/g-callback and click on create.9. Finally, you will receive the OAuth client ID and client secret. Paste these in the admin panel's genral settings section, in their respective fields.