I’ve always found Linux to be one of those things that you learn by necessity. Set yourself up with a Linux environment (Desktop, server, dual boot, USB boot, VM, whatever) and try to do something in it. If you’re using a desktop linux distro (like Ubuntu), still try to do things from the command line as much as possible. (For example, do some Googling to find out how to launch your browser via the command line instead of clicking the icon). Try to do something in that environment. You’ll probably have to go researching how to do it. Put the time in to understand what you’re doing instead of just copy-pasting into the terminal until something good happens.