Unzip the auransnd.zip, and put the auransnd.ftg file located within this zip file
into a directory $GAME\addon. If this directory doesn't exist, create it.

Edit the packman.cfg file located in the $GAME directory, and in the [sounds] section
of this file, add the line pack=$GAME\addon\auransnd.ftg.

This should be all you need, the next time you run the game you'll be running with the 
"fabulous" Auran sounds ;)

If this is the first pack modification you've made, then the [sounds] section of your
packman.cfg file will look like this.

[sounds]
pack=$GAME\sndfx\sounds.ftg
pack=$GAME\sndfx\auransnd.ftg

Happy hunting,

blahnana.