Open in notepad the panel.cfg file for the plane the GNS is to be added to the flight sim instruments menu. For example, the Mooney file would be located in "C:\Program Files (x86)\Microsoft Games\Microsoft Flight Simulator X\SimObjects\Airplanes\Mooney_Bravo" in the same of FSX.
In the [Windows Titles] section, add a new window definition for the GNS. In our case we used Window07, use the next available window definition number and use it in both Step #1 and Step #2.
window_size= 0.500, 1.000
window_pos= 0.000, 0.000
If Windows security doesn't let you save the file in it's current location, save it to your desktop and then you can use Windows Explorer to move it to the directory location.