The guide does require that you have some knowledge of Linux and various aspects of your choice of distribution. Some things you will need to know are how to install your distribution of choice on your PC, how to install additional software, gaining root access since some commands require it (goes along with installing software), user permissions, knowing how to find device paths for your hardware, and some very basic command-line knowledge. There is so much variation with Linux that it would be too hard to try to talk about these topics in the guide; a lot of distributions have some sort of beginner tutorials that should be read first.
Since the guide tries to be generic, it focuses on command-line utilities when there are GUI applications that can do the same thing. An example would be the mention of the two command-line applications useradd and passwd when the users-admin GUI app that is bundled with Gnome can do the same thing; I do mention users-admin in the guide briefly. However, it can't be assumed that a person has access to users-admin, especially since it is Gnome specific, but any Linux distribution will bundle useradd and passwd so those programs are covered in detail. Really, only part 3 has portions where you will need to use the command-line.