The compass, along with the map, is automatically rotated on your device so that it is oriented correctly for the location where you are standing. The "compass" rendered on the device also behaves as a skyplot.
The skyplot allows visualisation of both the bearing or azimuth (the angle of the sun relative to north) and the elevation of the sun relative to the ground (or how high the sun is in the sky). The azimuth is shown by the position around the compass and is relatively intuitive. For example a mark near the easterly direction indicates an azimuth in that direction which is 90 degrees from north.
The elevation of the sun at a particular time however, is shown by the distance of the sun marker between the edge of the circle (representing the sun on the horizon) to the centre of the circle (representing the sun directly overhead). A sun mark higher towards the centre of the circle indicates that the sun is higher in the sky and a mark towards the outside of the circle indicates that the sun is lower in the sky. The sun will be at its highest point towards the middle of the day.