Wot's up DOIT,
Firstly, TBG have a post somewhere on here about this but if you cant find it let me briefly explain:
Three wires
Red = supply
Black = Ground
Yellow = variable speed control
Its easy, just chop your yellow, it isnt needed.
Using a 12v supply, either mains adapter, car battery etc (bassically anything that has a 12v dc supply) contect red to live(+) and black to ground(-) and the fan will come alive.
You can run more than one fan off the same supply as long as the supply has a high enough amperage ( thats the push of current )
example.
my fans are ratted at 12volts dc with an amp rating of 0.34A or 340 milli amps.
that means that I can power two of them at full speed by using a 700 milli amp supply.
Personally, I use a home made power supply with variable output 8 - 14 volts where I can vary the power for different fans at different times but that is not for the faint hearted.
Hope this helped.