Your site is made up of 2 types of pages. Admin pages and Content pages. Admin pages are part of your site and cannot be added or removed. Only someone logged in with editing permissions can see your sites Admin pages. Admin pages are used to setup users, Content pages, modules and to upload document and image files.Content pages are used to place your site content on that you intend to display to your sites users. Your pages may be setup so that all users or only logged on users may access them.
The Content pages in your site or organized in a heirarchial fashion. Usually you will have several top-level pages with muliple sub-level pages beneath. The sub-level pages may have sub-level pages as well. This parent-child organization is used to dynamically build your sites main menu.
By default, Content pages are included in your sites main menu. Alternatively you may exclude any page from the menu (hide), create a path only to sub-level pages (disable), or set the page up as a link to a file or URL on another site.