Vim comes with great documentation built in already. The interface to the documentation is the :help command.

For an introduction, see :h user-manual.

Almost all Vim installations also come with an interactive tutorial:

$ vimtutor

Vim is decades old and still popular. You will find a lot of resources about it on the web, some better than others. The good ones are listed here.

Help us explain this better! File a GitHub issue at https://github.com/exercism/vimscript/issues if you have suggestions, or submit a patch with improvements to the https://github.com/exercism/vimscript/blob/master/docs/LEARNING.md file.