Okay kiddo, so a high commissioner is like a special ambassador who represents one country in another country.
But when we talk about the high commissioner of the Commonwealth, it's like a special title for an ambassador who represents all the countries in the Commonwealth in another country.
So Commonwealth is like a group of countries that used to be part of the British Empire. They all work together and help each other out in different ways. And they have this special person called the high commissioner who takes care of their interests in a country where they don't have their own embassy.
It's kind of like having a superhero who looks out for all the countries in the Commonwealth, making sure their voices are heard and their needs are taken care of.