First, you have to set your main drive as master with the pins and the new drive as slave. You connect the first connector on the IDE to the Master and the second connector to the slave. This should get you up and running.
The diagrams you need for how to set the jumper ion the pins of each drive should be on the drives themselves. Read each drive's diagram separately, in case the two drives are different.
By the phrase "first connector" techmo34 used, what he means is the END connector on the ribbon cable - usually Black - goes to the Master drive. Usually the middle connector is Grey and plugs into the Slave unit.
Of course, you'll need a power connection to the new drive, too - probably a 4-pin Molex connector coming from the PSU.