The following steps can be followed for enabling google sign in-
1. Go to https://console.developers.google.com using a valid google mail id. Note : If you are using Google Apps account, you need to enable Google Developers console as an account admin.
2. Click a new Project
3. In this project, create credentials by selecting 'Oauth Client id'. You will be asked to configure a consent screen. This screen will be shown when a user does a single sign on for the first time and it will inform the user the permissions that are being granted to the application requesting for access.
After this is saved-
4. Select the application type for which you are creating the client id. In this case, it should be 'Web Application'
5. Give a readable name and enter Authorized redirect URIs as the domain names as given in the accounts panel while creating your institute. Example : The redirect URI should be http://<your_webapplication_url>/authenticate. For example if your institution portal domain is myschool.raising.com then enter the value as http://myschool.raising.com/authenticate
Click on Create client ID to save the values
8. Now, you will be able to login using any valid google account (if it is mapped to a user in the portal). Also, before logging in, ensure that 'Enable Google SSO' is checked under General Settings for that school.
See the full process in steps here-
Step 1-
Step 2-
Step 3-
Step 4-
Step 5-