Using frameworks to handle the authentication of your PHP application is perfectly fine to do, and normally encouraged. They abstract away all of the complexity of managing users and sessions that need to work in order to allow your application to function.
That said, it is important to take a step back and understand how authentication works in PHP. This allows you to more accurately debug problems with framework authentication systems that you make common use of.
Creating an authentication system using PHP is pretty simple since PHP has many of the features and functions built in. In fact, frameworks will simply wrap this feature set into a coherent authentication model that can be expanded to introduce new features.
In this article I will go through the steps required to create an authentication system using PHP and MariaDB. I will assume you have some knowledge of PHP, but that you want to know more about how to authenticate users.