Detailed DemonIVR installation instructions please? 1970 duster

Update: I found out what the old regulator looks like and now understand where the yellow wire goes. I also understand the other two points where the red and ground wire go but I don't know which is which. What really confuses me is that I found one source saying that the ground goes to the socket on the passenger side of the car and the red goes to the middle, but I also have another little tin cylinder labeled "gas" with a black wire going to the middle socket. Black typically means ground, right? So why would a ground wire go to the same place as a hot 12v wire?

So to simplify my situation: I removed the old regulator which had 3 prongs, and I know that the yellow 5v wire from the DemonIVR goes to the socket on the right side of the board/driver side. I know that the black ground wire and red 12v wire go to the locations of the other two prongs, but I don't know which is which. I have an additional thingy that is screwed to the instrument panel with a wire going to the center socket.

One more question: I have only two screws to which I can affix the wires from the DemonIVR. The center socket has no screw to attach to, it's just a slot to stick a prong into. How do I reliably connect the wire to this socket? Soldering is a last resort. I "can" do it but I am not skilled at soldering, don't have good soldering tools and also the instrument panel is still attached to some wires and is hanging from the dash giving me just barely enough room to move around in there. I also don't even know if it is safe to solder these components (how much heat can the instrument panel handle?).