Okay kiddo, so way back in time, a very very long time ago, there was a man named Jacob. Jacob had twelve sons and those sons had families of their own. These families became known as the "twelve tribes of Israel."
Each tribe represented a different part of the family and had its own special name. For example, the tribe of Judah was named after Jacob's son Judah and they were known for being great warriors. The tribe of Levi was named after Jacob's son Levi and they were in charge of religious duties.
Each tribe had their own land too, kind of like a big neighborhood where they all lived together. And each tribe had its own flag to help people know which tribe they belonged to.
Now, the twelve tribes of Israel are very important to people of the Jewish faith because they believe that these tribes were chosen by God to be His people. Even today, people still study and talk about the twelve tribes of Israel and what they meant for history and religion.