BackGround Tips

The "background" can be whatever you want it. The only necessary thing from the training room prefab is the floor plane. Make it's as wide as you want and then you can throw whatever you want in the scene, asteroids, starfields, trees, monkeys, monkeys in trees. If you just want a simple background (a floor and walls) I'd say insert your own planes instead of dragging a textures onto the planes of the training room. Just match the planes up with where the floor plane is. If you move the floor plane your prefab won't work.