Hi, this is the tutorial you'll find in the GNS V2 X-Plane User's Manual. Although for the GNS, the same applies identically to the GTN, until the X-Plane SDK offers plugins a more elaborate way to add any 'gauge' to a 3D cockpit.
Introduction: differences between X-Plane and FltSim panels
in FltSim, there are panels, there are gauges that can be configured on a panel, a gauge is a flat render surface where bitmaps are drawn to and animated over. In the virtual cockpit, FltSim a