1. Explore the subject almost randomly. Neither depth-first nor breadth-first; just follow threads that seem most useful or most interesting. Books, articles, videos, classes, whatever - it doesn't matter as long as you don't get bored. Dabble in all of them. If there are any practical skills involved (motion, writing code, etc) start doing those immediately.
2. At some point you get the ah-hah! moment. It is like the fog lifts and you can suddenly see the landscape. You don't know everything but now it seems like further knowledge is just a process of filling holes. You wield your knowledge to accomplish what you need by filling specific holes on-demand. Everything fits together like jigsaw puzzle pieces.
The time between #1 and #2 can be short or long depending on the complexity of the subject. But the experience of #2 is a massive dopamine rush. The main thing you need is patience; don't get frustrated and give up, you know that if you just keep poking around, eventually that dopamine rush will come.
Had some fun a few years ago with toy projects. Can't tell its current state...