The settings panel controls the functionality of your site and lets you integrate with third-party services.
Integration refers to the process of connecting together different software services. The services communicate through an API (Application Programming Interface). As part of the integration process, each service must be made aware of existence of the other.
As an example, Google Analytics provides statistical reports for sites. Google Analytics is told the address of the site, and generates an account number. The site then connects to the Google Analytics API using the account number.
To change settings or set up integration with a third-party service, go into edit mode, click the panels button on the toolbar, and click the settings button:
The Settings panel will then open in a new browser tab, giving you access to the following pages: