Go to admin.google.com and select security:
Under Advanced Settings, select Manage API Client Access:
Find the client id in the json file you downloaded earlier. Paste that in the Client Name field.
In the One or More API Scopes field paste the following string:
https://www.googleapis.com/auth/admin.directory.group,https://www.googleapis.com/auth/admin.directory.user,https://www.googleapis.com/auth/drive
Click Authorize.
Next Step: Increase Quotas