This is a great tutorial from @MikeRaarupBirk (found it while surfing the internet) : "fucking make the shitty map, put spawn region, make a worldclasse, create key/portal sprite, make map to embedded resource, rebuild, and join the map."
but here is a more in-depth one. found this on youtube lol, didn't watch the vid tho, but hopefully it's good. LOL
After watching the vid i realize the vid is absolutely shit, but it might do, idk.