Logic behind booking system,Please help,urgent

hi guys, i got a question regarding room booking system. if i have a room for ppl to book, and the room got 24 slot and each slot is half an hour for people to book it. what should i program it or the logic behind it so i can store it into database so i can it to display out in a timetable(html table) with slot have been booked and slot haven been booked?very very urgent, hope u guys can help me?new to asp but boss asking me to do it.please help help me,thx a million

am i asking the riht place?if not can someone guide me to the solution?thx thx a million