either that or you do it the following way:
Depending on the style you use edit either the navbar or header template.
Look for the line that links to calendar.php.
Before that for example you could add something like this:
HTML:
<td class="vbmenu_control"><a href="link_to_your_file_">Description</a></td>
link_to_your_file: is the page you want to open when clicking that link
Description: What is shown in the navbar ^^
Life can be so simple sometimes, but i strongly recommend when running a forum like vBulletin to have at least a teeny tiny basic knowledge of html and php, as well as javascript. No offense, but if you can´t even put a simple link you should either RTFM or go to something foolproof ^^