Badminton Reservation

Hello! I am trying to make a system to reserve courts at a weekly badminton game. Reservations are in 12 minute segments, 4 people to a court. We would like to allow people to only reserve a 12 minute segment during the previous 12 minutes, IE you cant reserve yourself for 10 slots in a row. We also want people to get some confirmation of their reservation and be able to cancel. If you can help at all thatd be great, it is turning into a Lord of the Flies free for all there. Thanks!