Linux is a family of operating systems usually seen as "enthusiast" technology. The basics of Linux are simple, and anyone in the current year can switch to Linux. Any child, elderly, tech enthusiast, or tech illiterate can run Linux, even if they might need a little help. When switching to Linux, it can help to know basic CLI commands, and terminologies when making the switch.
Distro / Distribution - Commonly refers when an operating system uses the Linux kernel, or in some cases, BSD.
CLI / TUI - Refers to the text-based interface, typing commands to do what you want. CLI is short for Command Line Interface, and TUI is for Terminal User Interface.
Terminal Emulator / Terminal - Refers to the application used to run commands in a CLI environment, while in a GUI based environment.
Window Manager / WM- A graphical environment where you can open GUI applications in one of many WM formats.
Desktop Environment / DE - A graphical environment using a window manager, along-side other tools dedicated to things like sound, brightness, and sometimes special hotkeys.
GTK / Qt - Graphical libraries most commonly used in Linux, both having differences.
Panel / Dock - Part of a desktop environment where an application has buttons to open apps or deal with other functions.
Package Manager / PM - A built-in tool to a Linux distribution to download packages from a CLI command or GUI application.
Where to Begin
When switching to Linux, one of the most common mistakes is just diving in with an install and bare metal. While this isn't a wrong way to do things, it is always more beneficial to test in a virtual machine. There are several virtual machines for Windows and Mac, and make sure in your BIOS that virtualization is enabled.
When starting to look into Linux, focus on Ubuntu and Ubuntu alone. While yes, there are problems with Ubuntu, trying to find the best distribution in the sea of distributions is difficult. Jump on Ubuntu, and if your PC cannot handle the Gnome desktop environment - which is a system intensive desktop - there are several official Ubuntu flavors made by the community and many more unofficial ones in progress. Some good lightweight desktops are KDE, XFCE, LXQt, Cinnamon, and Lumina. All of these desktops have either an official flavor or unofficial remix available. KDE and Cinnamon are possibly better choices for any user. If you select an Ubuntu flavor or remix, understand that it is normal Ubuntu with a different skin or purpose.
Once you understand how your virtual machine works, and you installed Ubuntu or a selected flavor/remix, it is time to work. Understand what packages you can install, and which you cannot. Learn what apps you need to use. You get Firefox by default, and you also get an app store where you can use it to get applications without the terminal. The kind of packages you need to download on Ubuntu are Deb packages, which many applications and games support.
When using the CLI, unless you want to be an absolute power user, there are very few commands you might need to know. Many graphical applications can also help you without the need to run a CLI command. Some fundamental commands are touch, apt, dpkg, mkdir, cat, mv, rm, cp, and chmod. These commands are primary tools to get you running anything in a terminal. Touch creates a file, without writing to it. Cat can read and write to files. Dpkg is a tool to install packages from a file. APT is a dpkg frontend that also better supports downloading packages directly from the internet without a GUI. Mkdir can make directories. Chmod gives and takes permission from users to do something with a file, including execution. Mv is a tool to move files and directories elsewhere. Cp is a tool that copies a folder or directory to another spot. Rm is how you delete the files and directories you have. There are GUI tools that can do this stuff for you as well.
The last thing is to experiment. Feel free to see if you can get something to work, and if not, keep that in mind. Learning Linux is learning the limits and changes in what you would otherwise normally do. Linux isn't for everyone yet, but it is getting there, and this is a simple "let's get started guide." Always feel free to ask questions and to google when you are lost.