Logging your odometer start reading if the popup didn't show.

If there are issues with the odometer start popup that do not come up, follow the steps below to trigger it again:

Before you clock in, on your first purple screen of the day, click on Log travel claim: 

Fill in your start odometer reading (#1 on screenshot), and then click on the back button (#2 on screenshot):
 

Clock in, and then go about your day as normal.
  

At the end of your working day, click on the clock-out button:
 

Click on Log Travel claim again. Your start odometer reading should now be pre-populated, as you filled it in before clocking in. Fill in your end odometer end reading:
 

The difference will automatically be calculated, but you will still need to manually enter it under "Distance to claim". Lastly, click on "Submit Claim" at the top-right corner of your screen to submit the travel claim:
 

Once doing this the first time, the odometer start popup should reappear the next time you clock in. If not, there is still the way mentioned above to log the odometer start readings.