The tutorials in the main section of the website are are more cross-platform, meaning no-matter what operating you are using (Windows, MACOS, Linux) - The tutorials will easily be transferrable to that system.
In this Linux section, the tutorials are more Linux specific. Like how to use Linux or for software that is used on a Linux operating system, It may be available for a Windows operating system, but it may look a lot different when used on a Windows operating system.
Each Linux tutorial should have a main tutorial page with the turorial series grouped by topic with downloads (if any).
Each tutorial should have it's own Overview page to give you a general feel of that that tutorial is about.
Switching to a fully supported version of Linux is more secure than using one of the unsupported versions of windows. This site contains free video tutorials to help you get started using Linux quickly and easily.