The first part of this section of the vBulletin Manual deals with how the vBulletin 3 style system actually works, and includes a reference guide for various important elements.
vBulletin 3 Style Reference
The second part deals with using the tools provided to you in the Style & Templates area of the Admin CP.
The Style Manager
Note:
To modify the look and feel of your vBulletin forums, a knowledge of XHTML 1.0 and CSS 1.0 is required. To learn the basics of these markup languages please visit W3schools.com. If you have questions please visit our community forums.