Bookings of 30mins to start on hour & then to 15mins

I am opening bookings from 12pm (for 30mins) and running until 2pm. Then my team have a 45min lunch break. I would then like to start the appointments again at 2:45pm (for 30mins) until 5:45pm. I can't find a way to do this as MSBookings will only let me start at 3pm or 2:30pm. Can you help?