Social representation is like having a picture or idea in your head about something that lots of people in your community agree on. Imagine that you and your friends are trying to decide what to play. You might have an idea in your head about what games are fun and what games are boring, and your friends might have similar ideas. Together, you all share a "social representation" of what's fun to play.
Social representation can be about all sorts of things that people in your community might have opinions about, like foods, clothes, music, or even serious things like politics or religion. When everyone in your community has similar ideas about something, it can help you all feel like you belong together and understand each other.
That being said, sometimes social representation can be bad if it means that certain people or groups are left out or treated unfairly. It's important to remember that not everyone in your community will have the same ideas, and it's okay to listen to different perspectives and opinions.