"... What a chess master does not need to know.
(1) All the basic endgames. ..." - NM Peter Kurzdorfer (2015)
Knowing 99% of basic endgames is not knowing all basic endgames
so this isn't a very strong statement.
And what people say and do are, sadly, often different. I bet this guy knows a lot of endgame ideas and themes even if he's never read an endgame book.
I think the first steps in teach people about the rook is:
1. What is called.
2. Where it goes at the beginning of a game.
3. How it moves.
4. How to castle.