Okay kiddo, imagine you have a toy that you and your friend both really like playing with. But one day, you and your friend can't agree on how to play with the toy. You want to play one way, and your friend wants to play another way. So you both get really upset and can't figure out what to do.
Now imagine this happening with a big group of people who believe in the same religion. They all have certain beliefs and ways of doing things that are important to them. But sometimes, they can't agree on everything. They might have different opinions about how to worship, what their religious leader should be like, or what rules they should follow.
When this happens, it can cause a schism. That means the group splits into different parts because they can't come to an agreement. Each part might decide to do things their own way and have their own beliefs.
Schisms often happen in religions, but they can happen in other groups too, like political parties or sports teams. Just like when you and your friend can't agree on how to play with a toy, sometimes people have to go their separate ways when they can't agree on something important to them.