Another example app has joint PSABH Series.
In this example, a user want to reserve/book a rental item between 9:00 to 12:00, and successfully done that, but when another attempt to book between 10:00 to 11:00, they can’t book that, because the date and time are overlapped from previous booking.
And, when they change to other times, such as 13:00 to 16:00, booking is accepted.
This app can be extended to have more features, but to keep it simple for learning purpose, only core feature is implemented, which is prevention of conflicting reservation.