The dashes in the top of the screen indicate your journey progress, and progressively highlight as you get closer to your destination.
On Route Mode, the arrow displays your current direction opposed to on Compass Mode, where the arrow shows your the direction of your final destination.
On Route Mode, the number under the arrow shows the distance until your next turn. On Compass Mode, the number under the arrow shows the distance, “as the crow flies”, until you final destination.
The dot on the edge of the screen displays the direction of your next turn.