This is the Home page of this site.
More specifically it is the "Front page" of the first collection of this site. This first collection is called "Home". Other sample collections have been created. You can access them by clicking "Blog A", "Blog B", "Photos", etc. in the menu bar at the top of this page.
You can add collections at will. You can also remove them (including this "Home" collection) if you don't need one.