Take a minute and write everything you know on a topic from scratch then go to the page and see how what you wrote compares to what is there.
This is known as the Feynman technique. That is exactly how I passed all of my Six Sigma and other professional industry certifications the first time. This is how this website was made. It will 100% work for you.
Feynman Technique to Learn anything in 4 steps
(Sourced from Learn Anything)
1. Pick a topic you want to understand and start studying it. Write down everything you know about the topic on a notebook page, and add to that page every time you learn something new about it.
2. Pretend to teach your topic to a classroom. Make sure you’re able to explain the topic in simple terms.
3. Go back to the books when you get stuck. The gaps in your knowledge should be obvious. Revisit problem areas until you can explain the topic fully.
4. Simplify and use analogies. Repeat the process while simplifying your language and connecting facts with analogies to help strengthen your understanding.