Would someone please show me what files I would need to edit for this...

here is my test site www.truckimprovement.com/catalog.

I want to make the left side categories and boxes all look like one table, like this site www.prostreetonline.com and http://www.martelbrothers.com. I just want to know what files to edit to edit.

Also, I want to change the look of the product listings. Where can I edit the tables for this? For instance, if I wanted the product listings to look more like this: http://www.prostreetonline.com/buy/a..._intake/acura/ or this: http://www.martelbrothers.com/catalo..._F_page_1.html.

Any help with were I can find all of the HTML for my site design would be great. Thank you.