Websites are made up of Pages and Modules.
Pages: Pages provide a place for you to display your site content. For example, a site for your Church would have pages about your worship schedule, contract information and a map.
Modules: Pages contain one or more Modules. Modules are bits of functionality which can be added to a page. For example, a calendar page could contain an "Events" module with all of your calendar information, the "Contact Us" page might hold a Test/HTML module with you address and phone number.
The Basic Administration Guide here will be contantly updated to help keep you up to date with the new features available to you.