Simple Car Rental Booking Calendar

As a small rent-a-car company with 5 cars, I am currently managing bookings with paper and pen. I am looking for a basic, easy-to-use booking calendar, possibly in Excel, that will help me view car availability and track customer details. The calendar will need to be updated daily.

Ideal skills for this project include:
- Proficiency in Excel or similar software
- Understanding of basic database management
- Ability to create simple, user-friendly interfaces
- Experience in designing booking systems or calendars would be a plus.

Please keep it simple and straightforward as I am not very tech-savvy.