There should be a readme file in the pack.
If not, go to your HTC > Aces High directory, there will be a folder named 'Sounds' there. Rename it 'Sounds old'. Then you simply past the unzipped folder of all the sounds into the Aces High folder, where the original sounds folder was and name it 'Sounds'.
It should open up and have a list of folders for each aircraft and it should also have a list of individual sound files for check 6 sounds, chute sounds etc etc.
Simple.