How to make rules based on user?

Hello I really liked Cockpit and I want to start with it. I want to make a website by using Gatsby and React Native Expo as frontend and Cockpit with MongoDB as backend. So I wonder if there is some rules to make powerful use of Cockpit? Is there something to let me create admin, super admin and simple users. And another thing I want to know is the images and videos uploading? Where and How to store the images and videos?