I know nothing about dslr cameras?

I know nothing about dslr cameras. i want to buy one. I probably will go for canon because i already have two lenses. so all i need is a body dslr. i know nothing about dslr cameras. How do I know which one to buy? Is there some kind of categories of canon dslr cameras, or any dslr camera is good for me. how do you choose dslr canon cameras.