Navigate to the plugin configuration page, click the "Add New Provider" button (located either in the middle or top-right corner), select GitHub as the application, and copy the callback URL from the plugin and keep it handy, as you'll need it to configure GitHub as the OAuth provider.
Login to GitHub : Go to Github Developer and login with your account. Click on settings.
Select Developer Settings.
Create App : Select OAuth Apps and click on Register a new application button.
Enter app credentials : Enter app name, plugin homepage URL. Copy callback URL from the plugin and paste it under Authorized callback URL field.
Copy Client ID and Client Secret.
This step is optional. Follow this step if the email is returned as null while further configuring the plugin. Go to profile and set public email.
If Public Email field is disabled, go to Emails and uncheck the option Keep my email addresses private.