Create a folder in your missions folder called music.
Then, place your music file in the folder, it must be in .ogg format.
Then create a Description.ext file and place this in it.
class CfgMusic
{
tracks[]={music};
class music
{
name = "Whateveryouwantthemusicfiletobefoundunder";
sound[] = {\music\Musicfilename.ogg,db+30, 1.0};
};
};
Hope that helps.
Just remeber to replace the Musicfilename with the name of the music file.
And it will appear in a trigger or waypoint under music.
Or you can use the Playmusic command.
I also believe this belongs in the Sounds and Cutscens forum.