Welcome the the "MODS" folder, where you will be working if you install any mods.

Here are some links to tutorials you may find usefull:

Buttons:

Download the latest Buttons file (Do it now!)
http://specialaircraftservice.com/sas/index.php/topic,97.0.html

The Buttons file explained:
http://specialaircraftservice.com/sas/index.php/topic,21.0.html


Files you use when adding a plane:

About Plane and Weapons_ru files:
http://specialaircraftservice.com/sas/index.php/topic,830.0.html

Customise your air.ini:
http://specialaircraftservice.com/sas/index.php/topic,23.0.html


Troubeshooters:

60%CDT:
http://specialaircraftservice.com/sas/index.php/topic,22.0.html

5% and 70% CDT:
http://specialaircraftservice.com/sas/index.php/topic,20.0.html


And look around in those forums for other topics that may be helpfull to you.