I don't know how he learned, but I studied it through the very demanding, and worth every second, course from Coursera:
Hinton's Neural Network class was very challenging for me too, mostly because many of the concepts were unfamiliar to me. But again, I could re-watch whatever I needed to in order to get it.
Too bad they haven't offered it since 2013. I didn't finished it by them for personal reasons :c/