you buy a tank, saltwater, clownfish. combine together(water and fish go in the tank).
seriously its pretty easy if clowns are the only thing your interested in keeping, a regular filter will work. so the only things you need different then a fresh tank is a hydrometer and saltmix for the water
its not just as simple as but some salt mix it with water and then go get a clown fish that you know nothing of put it in the water and voila! ( wish it was that simple)
i want you to go and search for the book mentioned by mr reef.
if you cant find that PM me. i ll see what i can do for u.
but i got that book and a whole lot of other books and they have all helped me understand the concepts ideas, and so on.
to the rest of the guys that said go buy a fish and a tank, com'on guys, at some point u were all noobs, and didnt know wat a powerhead was, and dont any of you care for the life of a fish? do u want the fish dead in like 5 days ?
any way... mr . oscarlover61898 please let me know if i can be of any help to u.