So on my clone wars map, I am adding a stormtrooper but the sound for the gun is missing along with everything else. I tried to follow the tutorial on the missing sound FAQ page but i didn't quite understand it because in the tutorial they're adding the ATAT sound and not a gun sound. Any help?

there are stock sound files for each map and era combination. They contain all sounds that are needed for this map/era constellation.
So on the hoth sound file won't be any republic/cis sounds, or on coruscant are no vehicle sounds.

If you want the E-11 fire sound, you are looking for any stock sound file with gcw era. If you have vehicles, too, you need to get the sound file from a map with vehicles and gcw era.