How do I set multiple timeslots - if time is set to 30 min but I like to be able to book 2-3 time sl

How do I set multiple timeslots - if time is set to 30 min but I like to be able to book 2-3 time slots. so I can book 1 time slot of 30min but also b able to book 3 time slot of 90min
ex. booking 8:00 + 8:30 + 9:00 in one booking or even a full day.. is that possible ..??