Maybe try out my vi quickstart tutorial:
https://gumroad.com/l/vi_quick/
vi is the predecessor of, and a subset of, vim, and is probably available on even more platforms than vim is. So knowledge of that single editor (vi) enables you to work on any of those platforms. And you can always progress to (and through - it is big) vim later, at your own pace.
I wrote it at the request of two Windows system administrator friends who were given additional charge of some Unix systems. They later told me that it helped them to quickly start using vi to edit text files on Unix.
Another nice thing about learning Vi first: no plugins. There are so many plugins that make Vim _worse_. In my experience most novice vimmers end up with a huge vimrc, which overtime is pared down to something pretty small as they learn how vim actually works.
Yes, good point. That's partly why I mentioned that vim is big, above. And there is tendency of some devs (not just beginners) to load many plugins (for any tool, not just vim), before learning the base tool well. Counterproductive, IMO, plus leads to cognitive overload. And at least in the case of vi/vim, you can compose commands, so, even without using things like macros or plugins, you can achieve a lot. So master that first. It will take you a long way.