You can get a longer set screw at a hardware store, if needed.
It goes together as Roger indicated. Test to make sure the antenna comes down. If not, you need to change the pointer to coincide with the "set" position, and the antenna in the down position. You'll feel it set into the notch if it is correct.
Wayne MSGT USMC (Ret) & Earlene (CinCHouse) RVM14
Lexi - Goldendoodle
2015 Winnebago Tour 42QD
It is what it is, and then it is what you make of it.