A couple of questions
 

My Website is www.yousellstuff.com

1. I added a link to navabr, but it is a different color, why is this and how do i fix it?

2. I am making a new VB page and the first step is to save a file called test.php
Where do i save/upload this file to make it work with the template I made?

1: Try <td class="vbmenu_control"> instead of <td class="vbmenu_option"> for the contact us link.

2: Looks like you are using this so test.php would go into the same directory as the vB showthread.php file.

which is were what does that mean

Where is where you added the contact us link, presumably the navbar template.

no where does the test.php thread go

http://www.yousellstuff.com/showthread.php?t=1 => so that would be your main public directory.