what year is your MK3? pre 90? if you have the inslated(*edit INSULATED) wire CONSTANT ground, and the red to a positive that is switched or get's a pos signal from clutch, all you need now is the sensor wire to your CPS. pre 90 use the red/orange-ish wire from the CPS, as in it literally comes out of the CPS, not the harness going to that. On the thread where you bought the anti lag i posted a link. Also hold down the big button and rev to what rpm you want, then release it to set. If I set it to 6K, it retards to 4K and shoots fireballs. It doesn't sit there like a revv limiter. Once EVERYTHING is surely wired correctly, you can turn the level up from factory level 2, which is default, up to 10. i left it at 2 as I get great results as is. I will post this on my wall as well for convenience. Let me know what year your car is, turbo or non.