Okay kiddo, imagine you're going to a fancy hotel or restaurant and you have a car. When you get there, you might see a person wearing a nice uniform and a fancy hat. That person is a valet boy.
Their job is to help you park your car. But they don't just park it anywhere. They take it to a special and safe parking spot called a valet parking. They also help you when you leave, by bringing your car back to you so you don't have to go get it yourself.
It's like having your own personal parking helper. Valet boys are very polite and helpful. They make your visit to the hotel or restaurant nice and easy, so you can enjoy your time there.