In the Settings =>Design =>Site Content menu of the Left Hand Navigation, you will have the ability to add or otherwise edit additional pages and links on your store. The Site Content section is made up of two halves with the top half being for menu links (which typically appear in your store's top menu section), and the bottom half which is designated for extra page links (which appear in the bottom of your store's navigation).
Additional Pages can either be linked to existing fils on your site or otherwise edited to include your own content.
For an example of an additional page that is linked, look at the home menu link. This link on your store's menu section will be linked to home.asp. This menu link cannot have its own content added to it via the Site Content area because it is instead linked to your store's main home.asp page.
For an example of an additional page that has its own content, look at the "About Us" link in your store. This page is set as a link on the site, but its content is added directly in the Site Content section.
Another feature of the Site content section is the ability to use a database feed to populate the page's content. To see an example of an extra page using a database feed, have a look at your site's "Terms and Conditions" page. This is a page created for your store's terms and conditions which are populated on the page as a database feed.
Note: When using database feeds, you will need to set the page using the "Extra Pages" section of the Settings =>Design =>Site Content section.
For more information on using the Site Content section of your store, please review our knowledgebase article about the topic here.