Practice it end to end

Build a learning server from scratch and put it into service. Take a clean virtual machine with Ubuntu or Fedora, log into it as a regular user, and work through the steps in order. Each step leans on its own chapter of this level.

1. Create a working user with sudo and check right away that the privilege escalation works:

$ sudo useradd -m -s /bin/bash deploy   # -m creates the home directory
$ sudo passwd deploy                     # set a password
$ sudo usermod -aG sudo deploy           # add to the sudo group (wheel on Fedora/RHEL) without wiping the old ones
$ sudo -l -U deploy                      # see what it is now allowed to do

1. Install a service and enable it under systemd. Pick one, nginx