Create a software to check availibity of schedule

I am looking to have a software program created to check the availability of appointment schedules. The software needs to be windows based / web based, with individual logins for access for different accounts. This software should check availability for appointment slot available for book in. the target system is web based and it has different location for appointment slot. we will then specified the location we need (excample:- location A, B or C, that selected from the option / dropdown box from the website), time we need (should be a range of time, example:- 2pm to 4pm slot). we should then make the booking based on that automatically.