Each model's sounds goes in a folder named after the model, namely:
SEAFIRE, SPIT1, SPIT5, SPIT9, SPIT14, SPIT16,
and
A6M2, A6M5B.
The .wav files must be in the following format: mono, 22KHz, 8bit. (someone correct me if I'm wrong)
ENG.wav is the engine
ENGSTART is the engine start sound
ENGOFF, the engine off sound
FLAPS, the flaps
GEAR, the gear
M2, the external sound of the model's machineguns/cannons
20MM_1, 20MM_2, etc are the internal 20mm sounds. You should have as many of these as there are guns of this type.
30CAL_1, 30CAL_2, etc are the internal 30cal sounds, these work the same as 20mm - you can have as many as there are on the plane
STALL is the sound of the stall
WIND is the sound of air past +-300mph
I think these too can replace the default sounds if placed in a model's folder:
BUFFET
STRESS
etc.. The rest of them would be those you can see in the screenshot I posted in the previous post.