Hmm...this is quite easy. You need your ground (-12V), power (+12V) and the reference signal from the ignition coil (this would be the white wire in 1.6 8V, if I recall properly).
If you dont have a tach already, you will have to tap into the high voltage coil reference pulse signal. Is your engine running off a distributor cap, or off DIS? (I think its off distributor).
its got the dizzy hanging off the side of the engine... connected directly to the cam shaft... im not sure exactly what the ignition coil is, but i know the distributor is on the side of the engine