Three Column Template?

I am new to WordPress but like what I see. I would like to use a 3 column layout and have tried dots and vesivius, but am not quite there yet (they work, but look and feel is not what I want). I am considering alterations in this css style:
http://www.stijlstek.nl/demo/3colhf.html
The css is available at the site but I apparently need to change the template (index.php) in order to use this css style with WordPress. Can anyone direct me to a tutorial or other help? Is this too difficult a task for a newbie (willing to learn and persistent)?
Thanks!