The next connector is the rear connector. It includes all the lights, the pitot tube, the ELT. I didn't have the ELT ready so mounting the ELT and running its bundle was the next thing to do before I could do its plug.
I mounted the ELT on the panel I intalled 10 years ago. I had to remove it and re-drill new holes because the ELT no longer matched the hole arrangement I had prepared. But no problem. By now drilling out rivets is no problem.
The ELT has a small DIN connector that needs to be soldered to its wires.