This tutorial is about creating Google app for your website. You can create your own google app for your website login by following this step-by-step tutorial
1. Go to https://cloud.google.com/console/project and click Create Project
2. Click APIs & Auth > Consent Screen on left side and enter required data.
3. After Save, go to Credentials section on left side and Create New Client ID. In this section, provide callback url
4. Grab your credentials in final screen