Click on an existing booking in the Schedule, then click the three dots in the top right corner to display the Options menu. From here, choose Delete Booking for a single day booking, or Delete Entire Booking for a multi-day booking. If you've clicked on a multi-day booking, you'll also see the option to Delete [date] Only to delete just the date you clicked on.
Please note: You will need sufficient permissions in order to delete bookings. Please contact an administrator in your account if you need increased permissions.