The main navigation is created with definition lists, and the menu can be expanded to contain more links if needed. You can also use the main menu as an overview or a basic sitemap, and expand the site with subpages using the sidebar buttons or regular link lists. On sites with fewer pages, the definition list menu can be removed and replaced with an ad banner (600px wide) or a large logo. You can also place a horizontal text link menu in the the gray space between the header and the content, just to give another example. Feel free to experiment with the spaces to find your own preferred structure.