I'm only just getting to learn a bit about the moons but I struggle to retain the information given, how do you do it?

There is so much to it as well when it comes to signs and stars and planets and under certain moons that it seems to get really complicated. When the time is right and I can sit down to these things, I am going to jot it down in a book. But really, how do you know it's under cancer? I know moons can be noted on a calendar, easy, but the other stuff... its magical knowledge lol