Open Terminal. Run the following command: su - Enter the root password created in prior steps. Run the following command: sudo nano /etc/gdm3/custom.conf Scroll up the list using your keyboard ...

Also: The best Linux distros for beginners With sudo in place, users no longer had to change to the root user or log in to that account to run administrative commands, such as installing software.

The root can do everything but login, and specific users get the privilege to do certain things. sudo XKCD #149 (CC by SA 2.5) In the Linux world, sudo is very common.