Okay kiddo, do you know what "colonial" means? It's when one country goes and takes over another country, sometimes far away from where they live. So, "Dutch colonial" means when the Netherlands, which is a country in Europe, went and took over other places around the world.
One of those places was called "New Netherland," which is now parts of New York, New Jersey, and Delaware. The Dutch traded with the Native Americans who already lived there and built some towns and farms. They also brought over some enslaved people from Africa to work for them, which was very bad.
But the Dutch didn't just go to North America. They also had colonies in places like Indonesia, which is a country in Asia. The Dutch did some good things in those colonies, like building schools and hospitals, but they also made the people who lived there work very hard and took a lot of their resources for themselves.
So, Dutch colonial means when the Netherlands controlled other places and made decisions about how those places were run. Sometimes they were fair and sometimes they were not.