Hello.
Probably you are activated the check in/out time feature at the general booking settings page. If you need to use the check in/out time for the first and last day of selections instead of the time slots, so then you can activate/deactivate and configure the check in/out Times at the general booking settings page.
If you are need to use the time slots instead of the check in/out time for the range of days, so then please deactivate the “check in/out” time feature and configure the timeslots at the Booking > Settings > Fields page. Please read more about that here
You can change the time format at the general booking settings page, but it’s will work only for the time selections shortcodes and not the time entering shortcods.
Also please post all your future questions at the support section of the plugin site.