Okay kiddo, so you know how each country has their own leaders who make important decisions and rules for the people who live there, right?
Well, the leaders need a place to work from and make these decisions. This is called the seat of government. It's like a big office building where the leaders meet and work from.
Usually, the seat of government is located in a capital city. For example, in the United States, Washington D.C. is the capital city and it has a big building called the White House where the President lives and works from. There's also another building nearby called the Capitol Building where the leaders of the Congress work from.
So, basically, the seat of government is the place where the leaders of a country work and make important decisions for their people.