Installation of the aircraft can be done in 3 ways: 1. Installation in main Prepar3D Addons folder, usually: C:\Users\[Your-Name]\Documents\Prepar3D v4 Add-ons\ Copy folder 'ALPHA_MiG-25 Foxbat' to your main Prepar3D Addons folder. 2. Installation in custom Prepar3D Addons folder: A. Copy folder 'ALPHA_MiG-25 Foxbat' to your custom Prepar3D Addons folder. B. Got to the ALPHA_MiG-25 Foxbat\P3D_Addons_folder and edit in that folder the file to reflect your custom Addon folder. In the file you probably have to change the Path entries of the AddOns. In my case: E:\FS-Addon\Airplanes\ALPHA_MiG-25 Foxbat\P3D_Addons_folder, so : <Path>E:\FS-Addon\Airplanes\ALPHA_MiG-25 Foxbat\EFFECTS</Path> ... <Path>E:\FS-Addon\Airplanes\ALPHA_MiG-25 Foxbat\Gauges</Path> ... <Path>E:\FS-Addon\Airplanes\ALPHA_MiG-25 Foxbat\SimObjects\Airplanes</Path> 3. Classic way, also the only way to install in FSX: A. Copy SimObjects folder into the root of your Flightsim folder. B. Copy EFFECTS folder into the root of your Flightsim folder. C. Copy Gauges folder into the root of your Flightsim folder. NOTE: FSX and P3Dv3 users also have to: I. copy the content of the 'Gauges_FSX' folder into the main Gauges folder of your FlightSim folder. II. Rename the Panel.cfg file in the Panel folder to e.g. "Panel_x64.cfg". The rename or copy the file 'panel__FSX_P3Dv3.cfg' to: "Panel.cfg"