You dont have to edit any vbulletin php file to make new pages work. Who's online can be done using hooks.
php code is not supposed to be written in templates.
Hooks are needed only if you want to insert code into the existing pages. This thread is about creating new pages.
The idea is to have a new page. See the
countries page on my site for example.
For a general explanation of how templates and hooks work, see the vbulletin manual.