Online tutorials, especially YouTube videos are horribly inadequate for learning Linux, or any Programming Languages.
My response below is not only for you, but for other readers of this posting.
One site, the Linux Documentation Project
, does have a lot of good material for learning Linux
, the CLI or Command Line Interface, Bash
, the most common CLI, or shell, Command Line Tools
, and many other topics. Some are a little out of date, but is a great start.
As for test platforms, the best is your own copy of Linux, plus the docs mentioned above! I would recommend two different sites for Distros:
for a list of all the Linux Distros available, especially the Top 10
Linux Live CD
, for a list of Distros that can be run from a CD/DVD or installed onto a Flash Drive
Start here, and post any questions you might have!
Welcome, and have fun learning a great O/S!