Firstly it's got to have ABS, then when you switch on the ign 2 warning lights relating to the ABS/TC should light up. On a hard dash the ABS light is red and near the top IIRC, the TC is in the middle and is orange, it looks like 2 exclamation marks that have fallen over. It should light up breifly then go out, even before you drive away IIRC.
On the soft dash the ABS is again near the top and the TC is on the RHS of the instruments, it says TC and has a ring round it.
More technically, the TC block bolts onto the side of the ABS master module and has extra pippes and another bleed nipple, it's not very big though, about the sizie of a matchbox toy car IIRC.
It only works on the back wheels too, mine goes crazy if I drive in only FWD as it spins the wheels.
