How does this work?

The idea is that the crossbow will reload after you've fired once.

So when you want to shoot again, you'll just have to reload the crossbow and shoot.

It's unbalanced and OP.

You can create 3D models, but I don't know how to add them to the game, or how to fix the other listed issues.

The first one is that the crossbow will disappear after the first shot, but will return after reloading. It will also disappear after the third shot.