Postby Imaynotbehere4long » Sun Oct 19, 2014 10:07 am
I'm not completely sure what you're asking, but I'll do my best to explain what you can do.
First, copy SMBX's entire music folder and make a backup of it somewhere. Next, take whichever song(s) you want to replace a song on the world map, and give it/them the same name as a world map song (like smb3-world1.mp3). Now, just move the songs into SMBX's music folder, replace the existing files, and you're done!
Don't forget to move the backup music folder back into SMBX's directory once you've finished with the episode (this time, remember to back up your custom music pack).