HTML means hyper-text mark-up language. HTML is the way your files communicate with a web browser to determine WHAT will be displayed on your site. For all of you non-computer scientists there are many cheat sheets available online to help you with proper codes you'll need.

Web Monkey HTML Cheat Sheet

There is one great resource for all the basic tags.

In affiliate marketing the most important tag you're ever going to have to remember is the

a href="http://www.websiteimpromoting.com>Call To Action (Anchor Text) tag. That is the linking tag and putting your tracking links in effectively is the ONLY way to get PAID. So at the very least make sure those are properly inserted.

I use templates for my websites or have them built by somebody who really knows what they are doing. But it is helpful to know the basics so you can modify your files on your own and you don't get ripped off by a shady freelancer who charges you 300 bucks for 2 pages. It's also important to know the tags because tags are what style sheets use to determine HOW a site is displayed.