Dual nationality means that a person has two countries where they are considered a citizen. Imagine you have two different favouirte toys that you like to play with - you love them both equally! It's the same idea with having dual nationality - you belong to two countries, and you love them both the same way.
Let's say your mommy is from America and your daddy is from England. When you are born, you automatically get both American citizenship and British citizenship because your parents are already citizens of those countries. It's like having two best friends at the same time!
Having dual nationality means that you have the right to live and work in two different countries, and you get to enjoy all the benefits of being a citizen in both places. So, you can have an American passport and a British passport and use whichever one you want to travel or work in both countries.
But remember, just like having two best friends, there may be rules and responsibilities that need to be followed too. Each country has its own laws and regulations, so you need to learn about both countries and make sure to follow their rules. And just like how you have to divide your time between your two best friends, you may also have to divide your time between the two countries you belong to.