Well then, I must be a genious-steven-hawking-protege, because not even within 20 minutes of reading that site (and no prior knowledge of winapi) I was able to setup and create my first window and button. Despite how much I'd like to believe it here, neither winprog.org or MSDN is written in some unbelievably cryptic manner (moreso the first rather than latter) that you cannot surmise from the tutorials how to create something as simple as a button.
Believe me, I am glad that you got the help, but I am trying to take the next step and get you to be able to give yourself the help. If you need someone to spoon feed you each parameter of CreateWindow, then god help you when you begin to use MSDN.