go to ACP / Style Manager / Pick your skin / Edit Templates / Navigation Breadcrumb Templates / Navbar / look for : <!-- top nav buttons bar -->
then wherever you want to put your code you can
example: if you have a thread for your forum rules you can link to that thread like this:
<td class="vbmenu_control"><a href="WHATEVER THE LINK TO THREAD IS"><font color="#FF9900">Forum Rules</font></a></td>