Here you can change settings and add content which will affect the page you are on.
A Group is the basic container of content on a page. You can add an empty group, or a predefined group with sample content.
Arranging groups allows you to move your content anywhere on the page
Arranging Sections allows you to move sections around in a group and resize them
This allows you to view your site without the editing tools
The Page Settings box gives you a wide range of powerful tools to customize your page, such as the page title, keywords, Open Graph settings, and page background settings