Let’s start learning Linux.
Linux is a Core or a Kernel work as a backend of Linux Based Operating Systems. There are hundreds of Linux based OS or call Distributions is available and they are increasing in counts. you can check a list here.
What do we need : There isn’t any prerequisite for learning Linux. It will be good if you have command line knowledge and little networking concept.
Where i can try these things : Before starting you need to setup your system. You can install Linux side by side you existing system or if you don’t wanna take any risk you can use VirtualBOX or VMware Workstation.
I recommend to user VirtualBOX because it’s free and easy to use. You can take a quick look here, how to use Virtual Box or VMware.