If you have the standard "Aura" CD\Radio Headunit, then you can add a VAG 6 CD changer to it. You will also need the power cable for the changer, as they aren't already fitted. (Unless the car was previously fitted with a changer, and the cable was left....unlikely though)
The cable has a block connector that plugs in to the back of the H\unit.
Of the 3 connection sockets at the back of the head unit, the cable plugs in to the top one, and fits on the right end, as you look at it from the rear.
Easy to do..