How do i play music on a level?

[Tanshaydar]

void PlayMusic(string& asMusicFile, bool abLoop, float afVolume, float afFadeTime, int alPrio, bool abResume);

Plays music.

asMusicFile - the music to play + extension .ogg
abLoop - determines whether a music track should loop
afVolume - volume of the music
afFadeTime - time in seconds until music reaches full volume
alPrio - priority of the music. Note that only the music with the highest priority can be heard! 0 - highest, 1 - lower, etc

Simply:
PlayMusic("some_music", true or false, any float number, any float number, priority number higher is prior, true or false);

For this and more: http://wiki.frictionalgames.com/hpl2/amn..._functions