Use a text editor to open sound_resources.ini in the SOUND folder, you will see that example sound files are assigned.

Here are the comments/guidelines for the sounds tools (sound_resources.ini):

- All sound OGG files need to be in the SOUND folder. No spaces are allowed for the *.OGG filenames. 

- You can use the OGG_Maker.exe in the SOUND folder to convert .WAV files to .OGG

- The first number (500) after the sound filename is the default volume. Volume ranges from silent (-10000) to
  full volume (0)

- The second number (0) after the sound filename is the default balance. The balance ranges are mute left (-10000)
  to mute right (10000)

- There must be exactly 63 OGGs assigned in the sound_resources.ini file

- Sounds 1 - 10 are background layers that will loop. Sounds 1 & 2 are "On" by default. You may turn the background
  layers On/Off with the number keys.

- You do not need to exit the game to load new music files. While in-game, you may change the sound_resources.ini file. If you do that,
 hit 'enter' while in-game and type "/music" and then hit'enter' again to reload the sound_resources.ini file.