Basically, the cloudsphere/skysphere is a bigass sphere with clouds that you'll find in the
UTM. It's mostly used for scenic terrain, as you don't often see the sky ingame, but you
could use it, I guess, as it wouldn't be in the way for an ingame camera, but would only
become visible during cinematic. It's really not a very complicated thing to use:
Simply place it on the map and scale it so that it's larger than the edges of the map.