Copy all files to __FS9__/aircraft/AS 350 Ecureuil/
When windows asks you if you want to overwrite the old aircraft.cfg, click on yes.
The new aircraft.cfg contains the links to both the old textures [those were included in the original "AirStar AS350 Ecureuil Helicopter" download}] and the new textures you just downloaded.
If you have renamed the old textures, you have to edit the aircraft.cfg
Start your flightsim and enjoy.
If you like this aircraft, drop me a line at christianhaensel@hotmail.com