It covers the basics quite well. Then google the breed's association that you are interested in and find the latest averages for that breed, as breed EPDs are not apples to apples. Or, ask a breeder about it, if they know what they are doing they will be able to explain it to you.
There are a lot of topics concerning this on these boards as well and you may get accused of :deadhorse: but the search function here frankly stinks sometimes so I don't blame someone for re-asking a question.
The link redcowsrule posted is a good read but it would help to know what breed you're considering as there are differances. The basics are the same. For simplicity: BW(birth weight), WW(weining weight), and YW(yearling weight) are the expected differance in pounds between that individual and the rest of his particular breed. It's an average of what his ancestors have done until he has progeny of his own to judge him by. Since it's based on weight lower is usually better on BW and higher is better on WW and yearling weight. CED is Calving Ease Direct and takes a few more factors into account than just weight. Higher is better. Carcass traits are kind of the same, MARB is marbling and more is better. To get much deeper than that we need to know what breed you're looking at using.