Have you ever played with a drum or a tambourine? Percussion notation is like a special language that tells you how to play different sounds on those instruments.
When we look at the sheet music for a percussion instrument, each note is written down as a special symbol that tells you which drum or cymbal to hit, how hard to hit it, and how long to hold the sound.
For example, if you see a circle with a line underneath it, that means you should hit a snare drum. If the circle is filled in, that means you should hit it with the drumstick. If there's an X instead of a circle, that means you should hit the rim of the drum instead of the main part of it.
There are also symbols to show you how loud or soft to play, and how long to hold the sound. For example, a long line means to hold the sound for a long time, while a short line means to play a short, quick sound.
So just like how words make up a sentence, these symbols in percussion notation make up a rhythm that helps you play music with lots of different sounds!