@Thrash99 - as I recall it was pretty easy, though not clearly explained. I did some digging and found these instructions from Chalenge:
"The whole idea of this pack is to replace all of the sounds with the sounds of the actual planes, vehicles, and guns as much as possible. Of course, some artistic license has to be used for some sounds that are just impossible to get these days. I have done what I could, but at the moment the pack is still incomplete.
In this ZIP file there are four *.bank files. You want to put those four files in your "\AcesHighIII\CustomSounds\Desktop\" folder (see attachment).'"
Hope that helps!