Okay kiddo, the National Academy of Arbitrators is a group of grown-ups who help other grown-ups solve problems when they can't agree on what to do. These people are called arbitrators and they are kind of like judges, but they are not part of the government.
When two or more grown-ups have a disagreement, they might choose to go to an arbitrator instead of going to court. This can be faster and cheaper than going to court. The arbitrator listens to both sides of the story and decides what's fair.
The National Academy of Arbitrators is a group of these arbitrators who have a lot of experience and are really good at their job. They teach each other and share ideas to help them do their job even better.
By working together, they make sure that the grown-ups they help get a fair and impartial decision. It's like having a special club of helpers who make sure everything is fair and everyone is treated equally.