Extract the "aircraft". (This will usually create a folder named "aircraft").
Verify that in this folder there should be subfolders named model,gauges,sound,panel*,texture* ... etc.
(Sometimes when you extract a file this will create an "aircraft" folder and then create another "aircraft" folder whithin !)
There is also sometimes a Readme file ... read this !!
Move or copy the "aircraft" folder containing the correct subfolders (described above) to the FSX "Airplanes" folder
(depending, of course, where you have choozen to install FSX! but usually:)
C:\Program Files (x86)\Microsoft Games\Microsoft Flight Simulator X\SimObjects\Airplanes
If a folder named gauges exists in your "aircraft" folder:
Copy the FILES INSIDE the folder named gauges, to the FSX gauges folder:
C:\Program Files (x86)\Microsoft Games\Microsoft Flight Simulator X\SimObjects\Airplanes\IKARUS\gauges\*.*
To the folder
C:\Program Files (x86)\Microsoft Games\Microsoft Flight Simulator X\Gauges
Now you should be able to start FSX and select your new "aircraft".
If you miss any sound frome aircraft try to copy all sound files in the "aircraft" folder or in the "aircraft/sounds" to the FSX Sound folder:
C:\Program Files (x86)\Microsoft Games\Microsoft Flight Simulator X\Sound.
To be able to select various variations of the same aircraft (like Ikarus SE-YJL or SE-VKP) the box "Show all variations" must be checked:
There can be problems using older aircrafts if the "Preview Direct X 10" is checked ...
Try unchecking this ... Settings -> Customize (see image):
