there is a little more than that....
First off- TURN OFF YOUR COMPUTER!!! and unplug it aswell
then, you need to set the jumper to slave (see the hard drives manual or label on the drive) check your existing drive also because you MAY need to set that to master w/slave (if it has a setting for this)
once you have done this, plug the un-used ribbon cable connector and a 4 pin molex (power) connector to the HD, screw the HD in place and turn on your PC
here is a guide:
http://www.helpwithpcs.com/upgrading...hard-drive.htm