The compass shows the aircraft’s heading relative to the magnetic north. The compass is reliable in steady level flight, but it can give confusing indications when turning, climbing, descending, or accelerating due to the inclination of the Earth’s magnetic field. For this reason, the heading indicator is also used for aircraft operation, but periodically calibrated against the compass.
The input channel to the Compass widget is the angle on degrees (heading).
To assign channels to widget please take a look at the page Selected channels view.
On the image below the show direction is North. The number that mark the degrees have a factor of 10.