Two kinds of memory
Think of your mind as having a small desk and a huge library.
The desk is your working memory. It is where you hold whatever you are thinking about right now: the sum you are doing in your head, the directions someone just gave you, the sentence you are reading. The desk is small. Most people can only keep a few things on it at once, and they slide off fast if you get distracted.
The library is your long-term memory. It holds what you have learned over your whole life, from how to ride a bike to your best friend's birthday. It has room for far more than you will ever need.
Learning means moving things from the desk into the library in a way that lets you find them again.
Learning is building connections
Your brain does not store facts like files in a drawer. It stores them as links between ideas. When you learn that a tomato is technically a fruit, that fact gets tied to what you already know about tomatoes, fruit, seeds, and maybe that one argument at dinner.
The more links an idea has, the easier it is to find. Each link is another road back to it. That is why new material sticks better when you ask, "What does this remind me of?" or "How is this like something I already know?"
It also explains why the first steps in a new subject feel slow. You have fewer hooks to hang things on. As you learn more, new ideas have more to connect to, and learning speeds up.
Familiar is not the same as known
Here is a trap almost everyone falls into. You reread your notes, and they feel easy. Every line looks familiar. So you feel ready.
But recognizing something when it is in front of you is not the same as being able to pull it up on your own. A test, a work meeting, or a real conversation will not hand you the page. It will ask you to produce the answer from memory.
Rereading mostly builds that sense of "yes, I've seen this." It can make you feel more prepared than you are. Later lessons in this branch show better ways to check what you really know.
Try it
Pick something you read or watched this week. Close it, take a blank sheet of paper, and write down everything you can remember about it in two minutes. Then look back. Notice the gap between what felt familiar and what you could actually recall.