Ok...how do you play add on levels in Dark Forces?

I can't get them to work. I've gotten the game to work on my XP computer, and the sound seems to work...sort of...but the music is a no go, and I haven't a clue how to access add on levels. Basically, I dunno what I'm doing, and the little page of instructions from the df21 forums is not being any help. So please, don't just link me back to df21 or whatever...there must be someone here who's personally experienced what I'm trying to do?

There are a couple of older DF threads in the forum index, including this one, where you asked this same question several months ago. I gave you an answer then, which apparently didn't work. If you're still having the same problem I can't help you, but it would be better to use one of older DF threads rather than start a new one, or maybe try asking on the DF-21 forums.