Collegiality in the Catholic Church is like when you and your friends are playing in the park and you all agree to play a game together. In the same way, the bishops and the pope who are leaders of the Catholic Church work together and agree on things they need to do as a team. They all have different jobs, just like you have different jobs when you play with your friends, but they work together for a common goal.
It's like a big family where everyone has his or her own role to play, but they all have to work together to make the family happy. This is why the bishops meet with the Pope and share their ideas and thoughts with each other. They discuss what they should do next to help the Church and the people who believe in it.
So, collegiality in the Catholic Church means that the leaders of the Church work together as a team to do what is best for the Church and its people. It's like a big family where everyone is important and needed to help each other.