There are a number of shell commands throughout this guide, for navigating around folders and creating/updating files. It's perfectly acceptable to use your normal file browser and text editor to do the same thing.
For reference the following gives a very quick explanation of what each shell command does.
cd stands for "change directory".
By default your terminal will have a "current working directory", which then determins what files you can see/edit. This is much like having a single file browser window open, when you double-click on a folder it will "change directory". This command is doing the same thing.
List the files in the foo directory.
The -F adds a / to the end of directories to distinguish
them from normal files.
Displays the contants of the file foo on the terminal.
Put the string "abc" into the file xyz.txt.
This will create the file if it doesn't already exist,
and will overwrite any content that is already there.
NOTE: This is one > character
Append the string "abc" on a new line in the file xyz.txt.
This will create the file if it doesn't already exist.
NOTE: This is two > characters