Okay kiddo, have you ever heard of the word "Sanhedrin"? It's a special word that refers to a group of important Jewish people who make decisions about the laws and rules that people should follow.
Now, imagine you're playing a game with your friends, and you're not sure what the rules are. You might ask an adult or someone in charge to make a decision about the rules so that everyone can play fairly. That's kind of like what the Sanhedrin did.
The Sanhedrin was made up of really smart and respected Jewish leaders who would get together to talk about the Jewish laws and teachings. They would look at the texts and books that had been passed down for generations, and use their knowledge and experience to figure out what exactly those rules meant.
One of the most important things they did was to settle disputes between people who were arguing about what was right or wrong. Kind of like if you and your friend were having an argument about something, you might go to a grown-up to help you figure out who was right.
Now, the "Tractate" part of your question refers to a specific book of Jewish teachings that talks about the Sanhedrin. It's a really important book that helps people learn more about who the Sanhedrin were, what they did, and how they helped shape the Jewish religion and culture.
So, to sum it up: the Sanhedrin was a group of really smart and respected Jewish leaders who would get together to make decisions about the laws and rules that people should follow. The Tractate is a book that talks about them and helps people learn more about their important work. I hope that helps!