The Views/template directory contains a header.phtml and a footer.phtml which should be included on every new page generated. To add additional pages just edit the file header.phtml to add the extra link and then add a new Controller (pageN.php) and a new View (pageN.phtml), for each page required.
The Model code files are placed in the Models directory.
Do not change any of the css files in the css directory unless you know what you are doing!