generally, every motherboard has two IDE channels, each capable of running two drives. so that's a total of four drives you can use in IDE.
basically, all you have to do is plug in the IDE cable, plug in the molex (power) cable, and screw it into the case.
if you only have one IDE cable, look for where it comes out of the mootherboard. there should be a second IDE port (if the motherboard is like 99.9% of othe motherboards)
in this case, you can just get a new IDE cable, plug one end in the motherboard - there will be a plug in the middle of the cable. the plug which goes into your motherboard is the one further away from the middle plug
and then attatch the new CD burner to the other end of the cable.
Windows will automatically detect and install the new drive when you boot up.