Hi Anne
1. For not showing am-pm, you can go to Events Booking -> Configuration, find the config option Event Date Format, by default it is m-d-Y g:i a. You can change it to m-d-Y G:i for example
Do the same for Time format config option, it is g:i a by default, change it to G:i would help
See
php.net/manual/en/function.date.php
for list of parameters can be used
2. For not showing the other buttons, unfortunately, you will have to customize the code. The file you need to customize is components/com_eventbooking/view/common/events_timeline.php
Regards,
Tuan