heres how it goes:

red wire - tap into car's power. But, it has to be a power source that turns off when the car turns off otherwise you'll run out your battery when the car is off. Lol, theres plenty of other things to choose from other than the ignition coil, just look around a little bit and you'll find something.


black wire - ground

green wire - tap into rpm signal wire


and there you go. Thats all there is to it.