Hi,
I am Nallakumar. I have more than 11 years of experience in C# and MS Exchange & Office 365 APIs.
I am suggesting the following solution.
1. We will develop a C# Winforms/Web Application according to your preference.
2. That application will ask for the Office 365/MS Exchange URL and credentials.
3. After successful login, it will show a calendar to select a date.
4. Once a date is selected, the application will list the available resources in Office 365 and it availability for every 15 mins.
5. User can select any number of continuous 15 mins duration for a given resource and book that resource accordingly.
If you are choosing web application, I need a web server from your end to host the application.
Thanks,
Nalla