If you’re pursuing any IT certification worth having, you’re going to have to learn lots of stuff. The higher the level of certification, the more information you’re going to have to have crammed into your tiny little human being brain. The best way to get that information into your head is to teach it.
Even if all you’re doing is to keep a diary of your learning progress, the act of composing your thoughts to communicate them to another person will force you to both understand and remember the particulars of what you communicate. Copying and pasting what another person wrote won’t cut it: you need to rephrase it in your own words.
Yes, this takes on the risk of being wrong. That goes with being a human, so quit whining and hurry up and make your mistakes so you can get on with learning from them. If you come out and say something wrong, ask someone to correct you, check the suggested correction, and go forward from there.
But above all, if you actually put down something that’s accurate – and if you do all you can in order to *be* accurate – then you’ll learn that topic in the best way possible.