Ask HN: Best way to learn robotics with a 10 year old?

Hey all, after discovering the greatness of NHRL[1] my son and i would love to try building a small battle bot, but i know nothing of electrical engineering or robotics.

I prefer to learn how everything works and build something custom instead of just buying a premade kit and following instructions. I was wondering if there are any resources or books that we could go through together that would teach us the basics of electrical engineering and/or robotics.

Thanks!

[1] https://www.youtube.com/watch?v=1GzzckUcnfE