Select a project, or create a new one by clicking Create Project:
In the Project name field, type in a name for your project.
In the Project ID field, optionally type in a project ID for your project or use the one that the console has created for you. This ID must be unique world-wide.
Click the Create button and wait for the project to be created.
Click on the new project name in the list to start editing the project.
In the left sidebar, select the APIs item below “APIs & auth”. A list of Google web services appears.
Find the Google+ API service and set its status to ON—notice that this action moves the service to the top of the list.
In the sidebar under “APIs & auth”, select Credentials and in that screen choose the OAuth consent screen tab
Choose an Email Address and specify a Product Name.
In the sidebar under “APIs & auth”, select Credentials.
Click Add Credentials button and choose OAuth 20 Client ID.
In the Application type section of the dialog, select Web application.