They talk about the harness being able to connect to 2 drivers. That's what the second set of connections is for. I just installed my kit from them yesterday. It came with no instructions. I ended up using the shorter harness and cutting the longer one off leaving just enough to
Put heat shrink and tape on the individual conductors. I mounted the relay just ahead of the coils under the tank , put the driver up under the upper triple clamp and put the transformer ( last box before the bulb ) in the headlight shell. In retrospect I should have used the longer leads as I ended up extending the shorter ones by about 4". I ran 2 14 gauge wires from the battery. I took a black from the battery neg to the headlight shell and red from the top of the starter solenoid on the battery side. I put an in line blade type fuse holder with a 15 amp fuse on the red behind the left side cover. I tapped into the red to power an ignition coil relay under the tank to save my kill switch from the increased load from Dyna 3 ohm coils and then took the red up to the headlight shell to power the lights. Everything works !
Hope this helps
Mike