I removed a wing from a car and I cant re-add it. Why?

I removed a wing from a car and I cant re-add it. Why? I find this frustrating. There are locks everywhere. It is also buggy because I can rechoose some makes of car but cant do the ones under the lock in the middle.

I screwed around in it and got it unlocked, but need to rebuild the car minus the exterior, engine, transmission, suspension, wheels, areo the works......

I screwed around in it and got it unlocked, but need to rebuild the car minus the exterior, engine, transmission, suspension, wheels, areo the works......