Should only take you a couple of hours unless you take more time to make sure everything is right, neat, and tighty. The signal wire you need to connect into is the signal wire to the TPS. The zex system is activated at full throttle, so this is why you need to tap into the TPS signal wire.
Unless I am mistaken you have one of the zex smart systems right (not sure if that is the proper name but it comes with the purple box that controls everything, right?)