Google Oauth
In this section you can authenticate and request permissions to access your Search Console data. Once authenticated you can choose the site from the drop-down menu in the Options panel.
To enable the login button you must enter the cliient ID and client secret.
Options
In this section of the settings you can choose the site whose data you want to get. You can change the site at any time, in case you manage multiple sites and want to view data from another site.
If you want to display Search Console data in the post type table, you can choose which post types you want to display the data from.
To insert the verification metatag you just need a simple click. If your site is already verified you can avoid this step.
Google Credentials
In this section of the settings you can enter the Client ID and the Client Secret Of your project. If you do not have an active project consult this guide.
The client ID and client secret are the keys that allow you to authenticate yourself and receive authorization to have access to the Google services api. Do not share the keys with anyone. If you need to, you can always disable the Oauth key that is associated in the administration panel of the Google console developer.