I tend to learn best by example, so I learnt from;

https://stemkoski.github.io/Three.js/

http://learningthreejs.com/

https://aerotwist.com/tutorials/getting-started-with-three-j...

There are a few books about WebGL but the tech moves so fast they're largely out of date already. There's a tutorial series on Youtube too if that's your thing - https://www.youtube.com/watch?v=9fg93FzfamU&list=PLOGomoq5sD...