Before building the flaps and ailerons, the skin needs to be bent in the front similar to the rudder and horizontal stabilizer.

Then we installed the ribs inside
Insert the forward spar and Cleco the hinges on
Full view of temporary Cleco just to get a sense of the part

Then we rivet the hinges and push-pull attach to the ribs.

After Cleco everything and transfer drilling, we place sand bags on top and shim the supports until there is no twist in the piece. At this point we begin riveting from the back forwards.
Flip it around when we get to the front for easier riveting
Then on to the bottom side, leveling the wood supports with shims again to keep the part true and eliminate any twist
And that’s it for both flaps.