So lets get started, but first here are some links that will be useful throughout this post:
To create an app, go to the Google Developer Console and click 'Create Project'.
Fill in the Project Name and the Project ID and click 'Create'.
Navigate to APIs & Auth > APIs and under Social APIs click Google+ API.
Click 'Enable API'.
Navigate to Consent Screen page and enter your email address and the product name, then click 'Save'.
Once the client ID is created, the Credentials page will show two new important pieces of information, the client ID and the client secret. These are required for OAuth2 functionality used with Google+ API.