Hey, The three wires together are your power supply one is called hot otheris called common, and the single wire is your ground wire, on your new light, there should be 2 wires on it, hook the wires with 3 twisted together, to one of the new light wires, and the other 3twisted together wires, to the other wire on new light, and the single wire, will hook up to new light, where it says ground, or a green screw somewhere on it, may also have a plain copper wire no coating on it this will be the ground wire, so 2 groops of 3 wires to the 2 main light connections, and one single wire to ground on new light. Hope thats clear for you PS. MAKE SURE YOUR POWER IS OFF before doing anything at all OK