IFRAME templates are a little trickier than the standard HTML pages, but don't worry. They will become second nature to you as well.
The document floatingpage.html is the page that is pulled into the IFRAME located on the index.html page. You will notice that their are two sets of hyperlinks within this template set. Those outside of the IFRAME and those inside the IFRAME.
When creating pages that will pull into the IFRAME, use the floating page template, rename it accordingly and link the pages using the hyperlinks within the floating page.
When creating pages that require hyperlinks outside of the IFRAME use the index.html template for your new pages. Then edit the link name (two places) within the IFRAME source code.