So imagine you are playing with some toys with your friends. One friend has a big toy and the other friend has a small toy. The friend with the big toy keeps telling everyone what to do and how to play. The friend with the small toy starts to feel left out and wants to have more say in what they do.
Now imagine this is happening in a big country called the Ottoman Empire a long time ago. Some people in the empire started to feel like they didn't have enough say in how things were done. They felt like the leaders in the empire only cared about the big cities and didn't care about the smaller towns and villages.
These people started to believe in nationalism, which means they wanted their own group of people to have more power and control. They wanted to focus more on their own language, culture, and religion instead of just following what the leaders of the Ottoman Empire said to do.
This led to some people wanting their own country separate from the Ottoman Empire. They wanted to have their own leaders who understood their language, culture, and religion better. This caused tension and conflict within the empire, and eventually led to the breakup of the Ottoman Empire into smaller countries that we know today.