In Outlook as well as in Google Calendar, I just very freely type in the time and hit tab to go to the next field. Outlook and Gmail then automatically “reformat” the time accordingly.
For example, to input 3:47 PM as the start-time, all I type is:
then I hit tab to move focus to the end-time for the event.
(Both Outlook and Google also offer dropdown menus from the start/end-time input fields so you can utilize mouse-based selection if you so choose.)
Please please please implement a similar time-entry scheme in eM Client. Adding appointments to eM Client because of its time-consuming time-entry process is so painful right now.