Try doing some research with Google on the difference between wiring in parallel and wiring in series. Hell, if you look hard enough you can probably find a DIY tutorial specifically for wiring PC fans (search on this and other marijuana growing forums).
Here's an example of series vs. parallel:
Instead of an amp you'll have a power adapter. Instead of speakers you'll have fans. In parallel wiring the positive wires from each fan would all be connected together to the positive wire from the power adapter. Same with the negative wires. Parallel wiring is easier, so that's good.
If that's not enough to go on then you might consider getting first hand help, doing a LOT more research, or just using 120v fans that plug straight into the wall. PC fans aren't high powered items but there's still some danger of overheating something and causing a fire if you screw something up badly enough.
Good luck.