Everything is done in templates. One good feature that I use alot is "
Add Template Name in HTML Comments"
You can find it by logging into the AdminCP->vBulletin Options->General Settings->Add Template Name in HTML Comments->yes/no
Add the template name at the beginning and end of every template rendered. This is useful for debugging and analyzing the HTML code, but turn it off to save bandwidth when running in a production environment.
When you view the source you will see
HTML Code:
<!-- BEGIN TEMPLATE: FORUMHOME -->
That means that the Template named: Forumhome was loaded first, and you can edit that template by going into the admincp->Styles and Templates->Style Manager->and click on the expand templates button. Under Forum Home Templates, you will find the Forumhome template and many more that are used through out the loading period. Hope this helps.