There are tons of available open source CMS that you can use freely out there. But it'll be great to learn and understand what made the CMS especially in the area of PHP and database. Some of the crucial area that you need to learn:
- Create a database
- Connect to a database
- Display a form with two fields
- Save the form data in the database
- Display the saved data from the database
Learn more about how you can create your very own CMS
here
