A coronation is a very important and special ceremony where a person becomes a king or queen. It's kind of like a big party where everyone gets dressed up in fancy clothes and there's a big throne for the person becoming king or queen to sit on. During the ceremony, someone very special called the Archbishop puts a special crown on the new king or queen's head to show that they are now in charge and have all the power. There are lots of important people there, like other leaders from different countries and important people from the new king or queen's own country. It's a really big deal and a once-in-a-lifetime event!