[kh99]

I see that you've found the article on creating your own page. You can see in that code there's already a line near the top that defines THIS_SCRIPT. So lets say you call your new file about.php, and at the top you change the THIS_SCRIPT line to be

define('THIS_SCRIPT', 'about');

Then you can go to the navigation manager and create an About tab, you could set your "target url" to about.php and in "Tab Script(s)" at the bottom, enter "about" (no quotes) so that your About tab will be selected whenever THIS_SCRIPT is defined as 'about'.