You can change the time format and units from your eBike Flow app under the settings.
Open the eBike Flow app,
go to your app settings (the gear icon on the lower right side of the screen).
Find "Time Format & Units" in the general section,
select your preferred time format and units.
If you have an eBike display, the Units and Time Format settings will be synched to your eBike display automatically every time you connect your eBike Flow app with the eBike.