When I was young, I tried to learn this endgame from Pandolfini’s Endgame Course. While I understood the concept of shutting down the box, I found this hard to execute in practice. I discovered this video a while back, and I think the speaker’s explanation of Deletang’s Triangles is the best method of how to win this endgame: its easy to remember in practice and it is very efficient.
Anyways, I hope you enjoy!