A long time ago, there was a group of people who went to different places and took control of them. These people were called conquerors. When they took control of a place, they established their own way of ruling, which is called a dynasty.
So, a conquest dynasty is when a group of conquerors takes over and rules a place for a long time. They usually bring their own culture, language, and way of doing things. Sometimes these conquerors are welcomed by the people they take over, and other times they are not.
Overall, a conquest dynasty means that the people who took over the place continue to rule it for a long time, often changing things about the place they took over in the process. It's like when you play a game and you win, and then you get to make your own rules for how you'll play from now on.