Okay kiddo, so literomancy is a big word that means guessing the future by picking a book and opening it to a random page.
Just like how you might ask your magic 8 ball a question and shake it up to get an answer, people who believe in literomancy believe that books contain special messages that can help predict the future.
Basically, you would pick a book, hold it tightly in your hands, and then open it to a completely random page. You would then read the words on that page and try to interpret their meaning. Maybe they would give you a clue about something that's going to happen to you soon, or a piece of advice that you need to hear.
It's kind of like playing a mystical game of chance, and some people find it really interesting and believe in its power. But it's important to remember that it's just a fun way to think about the future – nobody can actually predict what's going to happen for sure just by opening a book!