Rather straightforward. But pay attention to the black cable above the white clip on the left as the flange (where you put the screw) needs to go under that cable

Don't forget to put the two speaker wires on the right back into the clip on the battery. Something pointy will help to tuck them in.

Also don't forget to tuck in the cable connecting the battery to the board. For me it took a bit of finagling, and I had to push down the wires coming out of the socket to move the battery in place.