Okay kiddo, so niqqud is something that helps people who read Hebrew to know how to say the words correctly. You know how when you read a book, you say the words out loud in your head? Well, niqqud is like a helper for grown-ups who read Hebrew.
In Hebrew, there are lots of letters that look similar to each other, and they can make different sounds depending on what word they're in. So, niqqud is like little dots and lines that go on top of or below the letters to show you what sound they make.
It's kind of like when you learn how to ride a bike with training wheels. The niqqud helps grown-ups who are learning Hebrew to say the words correctly, until they get better at it and don't need the niqqud anymore.