Criminal law is a set of rules that tells people what they can and cannot do. It's like a game with rules- if you follow the rules, you can play, but if you don't, you might get in trouble.
The people who make these rules are the lawmakers- they are like the people who make the rules for the game. The rules are written down and put into books called law books.
When someone breaks one of these rules, they might have committed a crime. A crime is like cheating in the game- it's against the rules and can get you in trouble.
If someone commits a crime, they might have to go to court. A court is like a place where they decide if someone has broken the rules or not.
The person who broke the rule is called the defendant, and the person who says they broke the rule is called the prosecutor. There is also a judge who is in charge of the court and makes sure everyone follows the rules.
If the defendant is found guilty of breaking the rules, they might have to do something as a punishment- like pay a fine or even go to jail. This is like losing a turn or getting sent back to start in the game.
So, in simple terms, criminal law is a set of rules that tell people what they can and can't do, and if they break these rules, they can be punished in court.