I came across this description of learning methods and it reminded me of some themes @Elliot has discussed as far as the ideas of practice and mastery.
New, complex ideas are difficult to wrap your head around when you consider them all at once. Research shows that people can only hold a small number of pieces of information in their short-term memories at once. When you’re repeatedly having to refresh your memory of fussy details to understand what’s going on, other information that you need to understand the idea gets constantly pushed out of your short-term memory, so a full understanding becomes somewhere between difficult and impossible.
If you instead break down the idea into simpler parts and thoroughly learn each part and the relationships of the parts to each other, you’ll be able to think about the parts more fluidly and on a higher level when you come back to the larger idea.
The act of splitting up an idea also forces you to understand the idea more deeply than you would if you simply copied and pasted textbook material or wrote down what someone said in a lecture and studied that.