If the 580 is mounted on the camera, it can trigger the other two 430s.
If you've got the foot-stand that came with them, they can screw onto any tripods you've got lying around, or even a gorillapod with its legs wrapped around the top of a chair (i do that too often). Or just sitting on a pile of books or something.
That's the cheapest and most annoying option (definitely doesn't look very professional, depends if you know the model personally or if you're trying to start a real business).
Better than that you can use proper lighting stands, with soft-boxes or umbrellas, either buy them or find somewhere around you that will hire them out (or find a new friend that happens to own some to lend you).
For a really cheap-option softbox, I just got one of these: http://www.ebay.com.au/itm/280787328442 - with my 430EX mounted on-camera it makes my shots look just that much better, and you can't go wrong for less than $5 shipped. (Yes, you can get professional ones, but this is definitely worth the money to experiment with). Haven't used it in an off-camera position yet, it's small enough that it probably wouldn't be the best more than a few meters from the subject.

As to where to mount them, that's where help from others comes in, but it depends on what effect you're going for. Presuming you've got the 580 on-camera, the basic setup would be to have that fairly low-power, the 430s to each side and maybe a bit higher-pointed-down (umbrellas help), one higher and one lower or the same power as the on-camera, or just both higher (the basic studio setup). Learning about flash-grouping and ratios is very useful.
Or both on the same side and the 580 on trigger-only.
Or both behind, one pointing forward to make a silouette, one backwards lighting the background.
Or the 430s on the floor pointing up for those evil-eye shadows (if you really really want that effect).

Basically, just experiment for the effects that you might want. Having a very patient model definitely helps...