Agree the built-in 'documentation' and website are not very useful for showing the best way to do things. I find their wiki[1] to be a good source of practical information about using ffmpeg. It tends to expand on detail in just the right places and gives good examples. I find myself referring to it when I am tweaking command line arguments. My DDG searches often ends up at this wiki too.

[1]: https://trac.ffmpeg.org/wiki