How is a wing joined to the fuselage?
The main wing comes in two pieces, left and right wings, and they are bolted to the lower center fuselage section, which also houses the center fuel tank.

Fuselage/wing fillets (fairings) are added after.



The frame you captured shows the rear wing—the horizontal stabilizer. It is slid in and then bolted, more precisely attached to the mechanism that moves it.



(Same video)