The video shows what connection. Thereās a gray wire in the harness from the body of car to door harness . Thatās the positive wire. Same color on both sides. Your ground is the metal of the door behind the panel. The video shows both.
Did a video on YouTube showing how to install door projectors on us version Supra. Sorry for the audio and video. Didnāt have my GoPro. Used my phone.