sry, had to do it ;)
anyway, browse the forums and you'll find a lot of answers. if you get stuck with something particular, then ask.
and the answer to your second question: it doesn't involve prgramming actually, just "describing" (if you know html you'll understand what i'm talking about). if you want you can program too with mzscript for example, but that's advanced themeing already.
my suggestion is: learn about OTS, download some OTS-themes you like, install them and try to find out how they work :)