Okay kiddo, so a long time ago, there was a big disagreement in the church, and it caused a split.
You know how when you and your friends can't agree on something, you might decide to go play with different kids for a while? That's kinda what happened here.
The disagreement was all about how people should worship in certain parts of the world, specifically Italy, Africa, and some other places. One group of leaders, called the Pope and his friends, wanted everyone to worship the same way, no matter where they lived.
But some other leaders, like one named Theodore, thought that people in different areas should be allowed to have their own special traditions and ways of worship.
The Pope and his friends didn't like this idea, and they got really upset about it. They said that Theodore and his followers were wrong, and they were going against what the whole church believed.
Well, Theodore and his friends didn't agree with that, and they refused to change their ways. This caused a big divide in the church, and eventually the group that followed the Pope became one big part of the church, and the group that followed Theodore became another part.
So that's what the schism of the three chapters was all about - a big argument over how people should worship in different parts of the world, and it caused a big split in the church.