New to Hookah, Need to know all about it?

So I'm Thinking about buying a hookah, Ive smoked hookah a couple of times and really like it. But I don't really understand how it works. I know you put some shisha in it somewhere, which is tobacco, and you put a coal on the top. But where can I buy shisha, and what about the foil, and the water. Also I heard you can put marijuana in it, not saying i would but if i were too how would i go about doing so? I just want to know all there is to know about hookahs and how to use them correctly. Thank you!!