Being fairly "old school" and largely self-trained, I'm used to writing instructions about how to use a certain feature (Do 1, do 2, do 3, you're done). Recently, I've been challenged to also document why, which I interpret (though I could be missing the point) as the rationale for using a feature or "what this does for you," rather than "what this does."
So naturally, I tried "Googling" how to document "why" and surprisingly came up with nothing, or at least nothing I could find in a few seconds of scanning the search results.
I thrive on examples, so if I could see the difference, I'd probably be able to understand it. I'm throwing myself on the mercy of the forum members and asking for samples or ideas about how to document "why".