When you create an event in your calendar, you can modify the time duration using the beginning and ending time settings in the event editor. However, with this quick method, you can set the default time duration you want with a click.
If you are on a week or day view, simply drag over the 1/2 hour slot, then release the mouse. The event editor will open with 30 minutes as the default booking time for the event you’re creating.
You can modify this to your use. Set the default time duration by dragging your mouse over the amount of time you want for each event. For finer control, adjust the time resolution on your calendar. This enables you to easily adjust the event duration for smaller blocks of time.