With my kid, he just gets on Steam and starts doing his thing with his friends like everybody else as if he was on Windows. It makes no difference to him. I figure I'd let him learn the same way I learned computers, by just standing back and letting him poke and prod around and giving assistance and guidance when necessary. He can't break anything important.
I tried this with my son, who is now 17 and not nearly as computer literate as I was by his age, let alone Linux literate at all. I think it's a generational thing, as a kid growing up in the 90s I HAD to learn how to administer our PC at a higher level to do the things I wanted to do. Now with easy apps and tablets and auto-installation of all-the-things you just don't need to be an advanced user to do what you want to do. This is just my experience, YEMV