The new harness plugs into the stock drivers side headlight connector. Remeber the stock connector needs the low beam and ground wires switched. It should look like this:
The new harness gets grounded to the chassis and gets 12 volt + power straight from the battery. Then you jauts plug the new harness into the bulbs. You cant remove the stock harness because you need it to activate the new relays. They are what turn on the lights and switch the high and low beam.