Okay kiddo, do you know what a protocol is? It's like a set of rules and guidelines that people follow when they're meeting important people or when they're hosting big events.
So, the Chief of Protocol is someone who works for the United States government and their job is to make sure that everyone follows these rules when important people from other countries come to visit the United States.
Think of it like this - when you have a friend come over to your house to play, you might tell them what the rules are: take off your shoes, don't jump on the couch, ask before you eat any snacks. The Chief of Protocol does the same thing but on a much bigger scale. They help make sure that the visiting leaders and important people from other countries feel welcome and comfortable when they're in the United States. They might help plan a big dinner party with fancy decorations and make sure everyone knows who is sitting where. Or they might help plan the schedule for the visitors so that they can see lots of different parts of the United States and meet lots of different people.
Overall, the Chief of Protocol has a really important job in making sure that visitors from other countries feel respected and welcome when they come to the United States.