Have you ever played a game with a friend where you watched them play and made sure everything was fair? Well, that's kinda what United Nations military observers do! They go to different countries where there might be conflicts or arguments going on, and they watch to make sure that everyone is playing by the rules and not hurting anyone else.
The United Nations is a big group of countries that work together to help make the world a better and safer place. The military observers are sort of like the helpers of the United Nations. They make sure everyone is playing nice and that no one is getting hurt. They do this by watching what is happening and reporting back to the United Nations so that they can help find ways to solve any problems.
So, imagine you were playing a game with some friends, but one of your friends was always breaking the rules and making it so the game wasn't fun anymore. You might not know how to make everything fair and fun again, but you could tell an adult who could help you figure it out. That's sort of what the United Nations military observers do too! They tell the United Nations when people aren't treating each other fairly, and then everyone works together to find a solution. And that's how everyone can keep playing the game happily and safely.