Map mode is the default view when you begin navigation. You can rotate the dial to zoom in and out of the map. The time is shown in the top left, your speed in the top right, and the current road on the bottom.
If traffic data is available you will see traffic as different colors on different roads. Your current route will show in blue.
Your turn-by-turn directions are displayed on the bottom. You'll see the distance until the next turn, the type of turn, and the street name. If there is another turn coming up shortly thereafter, it will show above the distance to next turn. Zoom out all the way to see a trip overview.
You have several options while driving with the map mode. First tap the dial and select Options within the Quick Menu. From there you can end a trip, disable traffic, mute turn-by-turn audio, and report map issues.