How to learn and teach a subject (my own understanding, not 100% what the article says):
- Create a notebook and write down what you know.
- Create another notebook and write the same things down in a way that you can read it to a child and they can understand. Do this by actually reading it out loud. Take note of where you stumble.
- Open the first notebook again. Write down whatever you find you do not know or understand.
- Iterate.