I can help you a bit with the terrain maps and the masks. c: Also, I'll tell you how to put music in.
In the map maker (tools, map maker) in the second tab there should be a form that says music. Put the music file you want to use in C:FeralHeart(or FHPLUS)/Media/Music and then put in the file.(Ambient.mp3, etc.) It should work.
![Cheesy :D](https://feral-heart.com/smf/Smileys/default/cheesy.gif)
Be sure to save it. You do the same thing with the terrain and masks once you have them made. Save them as PNG's and put them in your Media/terrain files and make sure they're named like mapnameTerrain.png and mapnameMask.png or else there's a chance it won't work. If you're having trouble /making/ the terrains and masks, I have a secret that'll help you. :3 If you have a msn, tell me, because it'll help me with explaining to you how to make them.