"Follow Me" will automatically center itself on your position and, above zoom level 12, will automatically rotate with your heading.
Press the lower-left button to zoom out, press the lower-right button to zoom in. Zoom levels allow you to switch from an area as large as France to a single neighbourhood. The lower you go, the more detailed the map becomes.
Press the lower-center button to switch the informations shown at the bottom :
current speed and current altitude,
average speed and altitude climb,
current log distance and duration,
satellites in use, battery level and current time.
Image on the left is a true 1:1 screenshot from the device.