When I was in Engineering college, the one software I had time to understand is Arena. It is a simulation software used in simulating Manufacturing processes from start to finish. The software is hard to learn especially when the software didn’t work on my laptop and I had few hours to spend every week learning the software. I applied some Elon Musk principles for learning to it and the results shocked me. I never thought I would get an “A” in that Lab report.
Back to the question; When Elon visited Russia for finding rockets for testing them to make them reusable, they refused and so Elon Musk start studying everything he could about Rockets. This is where he started to use the first principle.
Elon Musk reads a lot and probably this helps him building disruptive technologies like building reusable rockets, Electric car companies, an Internet company that uses Space satellites, and solar panel manufacturing.
Learning The First principle:
The first principle is that “you think like a scientist”, you devise your own methods. If a product is costing you $150 and you are interested to produce the same product, it might cost you less than $80 if you know the process and arrange all the raw materials required for it. If you are interested to make a factory that sells a product “A” cheaper than the rest of the companies, this is what you can do.
Learning about anything should start with learning the very basic components of it. The first principle is also called “the building blocks of true knowledge”
Elon used the first principle when he returned from Russia unsuccessfully acquiring a rocket for making it reusable. He learns the basic of rocket building and finds out that it is actually cost less to build a rocket then buying it.
By using knowledge as a tree:
In one of the Reddit AMA's (Ask Me Anything), Elon Musk replied to a comment about learning, and here is how he replied to it.
“One bit of advice: it is important to view knowledge as sort of a semantic tree — make sure you understand the fundamental principles, i.e. the trunk and big branches, before you get into the leaves/details or there is nothing for them to hang on to.” Source
Giving an analogy of a tree with knowledge could be confusing. Even the first principle for learning anything starts from the bottom and goes to the top, the concept of a tree starts from understanding the big things and then going for the minor details.