I attached the RF brown ACC wire to the DGD ACC2 brown wire. Per the DGD instructions, the first push of the start button turns on the ACC2 circuit. The second push adds ACC1 and ignition circuits. So the ACC2 acts most like the ACC position on the standard ignition switch. I did use the ACC1 wire, through a breaker, to power a USB accessary port since it was an available circuit. But unrelated to the overall start function. Easy enough to leave it unconnected if you don't want to use it.

The Purple wire just goes to ground. I don't exactly understand the explanation in the DGD instructions. But that's I did and the system works properly.

Haven't installed the GPS option pictured. But it appears that relay is just interrupting the blue start wire when signaled to do so. So you'd break the RF blue start wire and attach the red and blue wires in between as shown.