Paypal and Categories help!!

I just made a website. I have switched from a few different formats, but I like wordpress the best. It is very similair to ebay. I have experience working with making ebay listings, and working with html, but not very much any of working with a website. Idk if this is the best place to post, so if not please move, but. With that said..

I want to make a website to sell electronics on. I have a template now, and I know how to use the basic templates like adding pages and stuff, but I am having a lot of trouble creating catagories like HARDWARE>NOTEBOOKS>MAC>MAC BOOK PRO… and then even if I had that I wouldn’t know how to redirect people to PayPal. I know this is very broad but I really want to get this to work, and am willing to try as hard as I can if anyone could direct me in the right direction. I have browsed on the forums for a few days, and googled and viewed tutorial videos, but nothing is helping me too much..