What should I do to understand complicated artistic concepts better?

I didn't take drawing """seriously""" until middle school, but I can't recommend enough the benefits of copying other drawings. NOT posting them and claiming them as your own, just for practice. People will tell you that you just "gotta find your own style" and that's a lie, you gotta find some other style that works for you and make it your own with enough practice.

I love the Avatar style of drawing and animating humans, so the most helpful thing for me was watching some of the show, taking screen shots, and just re-drawing those screen shots until I got a better idea of how faces were shaped, where the eyes sat in relation to the nose, how things look from different angles and expressions. In terms of animals, I copied a lot of Disney stuff. But Avatar and Disney are their own things, so there comes a point with enough practice where you can start visualizing poses and figures without finding an exact screen shot of what you're thinking of, and you might make stylistic changes that just look better to you and fit the scene better. Boom, now you have your "own style."

It really comes down to practice. You can start with references, but practicing is what really makes a difference. I recommend something like Inktober or some other drawing challenge that has you drawing daily, and you'll be able to see change throughout the month/duration of the challenge.

Hopefully this'll help you get off the ground!