All I did was install the headlight, put retaining ring in place, took pliers and gently squeezed the retaining ring until the OEM screw and nut screwed together. The pliers jaws hook on the small tangs right where the screw goes through in order to squeeze the retaining ring together. It's not that hard.
From my investigation into Daymaker headlights , final purchased and then install I found there are a lot of china aftermarket headlights. If the lights are under $320 each I would be very cautious. Especially if they "several colors to choose from"