Typical time calculation

1. To choose start time for A mark tap on it's time on the top (and it will highlight), then tap on the spiral somewhere near the desired time. You can adjust the time to a precise value moving your finger in a clockwise or counterclockwise order.
2. Tap on the B mark and similarly choose desired final time.
3. The time in the right up corner will show A and B time difference. You can tap on it too!! to change it from result to (24:00 - result).

*This will calculate for you time difference between two timestamps within 24 hours from each other.