Hi, so I modified the html file for the game a little bit to add the music from external audio files. It's not a super clean way to do this, but it works if you're just doing something small like I was. Essentially, I checked the room transitions and if the player was going into a specific room, I would change the music.
First at the bottom of the game's html file, I added this code so there's audio element with an id that I could call.
Then, I added code here to check for the room transitions.
Note that I changed the src to "" when I didn't want any music in a room. Also, make sure your audio files are in the same folder as the html file. There are many other ways to do this, and depending on what exactly you're trying to do, you will need to modify the code differently.