Riveted on the flap hinge, which completed the flap.
I was going to put the wing on the table and start the pushrods, until I remembered that EVERY part for the pushrods, except the pushrod tubes themselves, are on back order, and have been since January!
So all I could do was fill the aluminum pushrod tube with primer and slosh it around to coat the inside. I guess I'll start on the LEFT aileron and flap,