Always run X-Plane.exe as an administrator to ensure it has the necessary permissions to access all files.
If it contains aircraft folders (like a Boeing 737), move the folder to: X-Plane 11/Aircraft/ or a subfolder like X-Plane 11/Aircraft/Extra Aircraft/ . X-Plane-11-TRNT.rar
The installation path depends on what is inside the .rar file: Always run X-Plane
Right-click the .rar file and select "Extract Here" or "Extract to [folder name]." 2. Identifying the Content X-Plane-11-TRNT.rar