Okay kiddo, let me explain what Macedonian Bulgarians mean. You know how people can belong to different countries, like how we are Americans? Well, in some places, there are people who identify with different groups or nations even though they live in the same country. In Macedonia, which is a country in Europe, there are some people who consider themselves Bulgarian and also Macedonian.
Now, you might be wondering why someone would identify with two different countries. Well, a long time ago, the region that is now Macedonia used to be a part of Bulgaria. However, over time, it became its own country. But even though it's its own country now, some people still feel a strong connection to Bulgaria because of their history and culture.
So, these people call themselves Macedonian Bulgarians to show that they are both proud of being Macedonian and Bulgarian.
Does that make sense?