Here's the installation. You'll need to cut the wires on the harness to keep things tidy.
1) The two yellow wires go to the yellow wires on the lower GI connector, on the left hand side of the screen. They can go either way around.
2) The red and white wires connect to the two flashers underneath the target bank. The flashers are connected together with yellow wires. Solder to the extension flasher.
The red wire goes to the flasher terminal that connects to the two red wires. This is the 20V supply.
The white wire goes to the terminal that connects to the blue-brown wire.
3) When you are done, feed the black cable through the hole at the end of the target bank, and assemble the cable and ship on the top side. Use the cable ties to dress the wiring.