Okay, so a republic is like a big club where people get to decide who gets to be in charge.
In this club, everyone gets to have a say in what happens. They pick people called representatives to make decisions for them. These representatives work for the people and they have to follow rules on what they can and can't do.
So instead of just one person making all the decisions, the people get to choose who makes the decisions for them. It's like all the members of the club get to vote on who should be their leader.
They also have something called a constitution which is like a set of rules that everyone has to follow. This helps to make sure that everyone is treated fairly and that no one person or group has too much power.
So a republic is a bit like being part of a big team, where everyone gets to have a say and work together to make things happen.