Take the cover off the Gimbal board, and the retainer plate off the contact board. Both the boards have the connections marked on the respective board. Refer to Attachment 1(CG03 Removing the Three Black Wires) of the PDF document attatched to
Way To Fix Drones project for specific guidance.
Warning!! I see you have the pigtail plugged in with the remains of the black wires still connected. That is how these boards get blown up. All the bare ends of the broken wires are energized. The ones still connected to the contact board are energized directly from the drone. The ones still connected to the gimbal board are energized from the gimbal board. If any of the ends touch each other or anything else on the board, the gimbal board will be ruined.