Okay kiddo, so a long time ago, there was a country called Czechoslovakia. It was made up of two different groups of people - the Czechs and the Slovaks. Think of it like having two different groups of friends at school.
At first, everyone was happy living together in the same country. But as time went on, the Slovaks started to feel like they weren't being treated as fairly as the Czechs. It was kind of like they felt left out of some of the games the Czechs were playing, or like they weren't getting as much attention from the teacher.
So, some of the Slovaks decided they wanted to have their own country, separate from the Czechs. This was a big decision, kind of like deciding to move to a new school.
But before they could do that, they had to figure out how to make it happen. Because they were all living in the same country, they needed to have permission from the Czechs to leave. And the Czechs weren't too happy about the idea, because they didn't want to lose their friends, the Slovaks.
So, the Slovaks had to talk to the Czechs and negotiate a way to peacefully split up the country. They talked and talked, kind of like how you and your friends might talk over a problem until you come up with a solution.
Finally, in 1938, they agreed to split up the country peacefully. The Slovaks would have their own country, named Slovakia, and the Czechs would still have Czechoslovakia. It was kind of like playing on different playgrounds - everyone was still friends, but they just weren't playing together all the time anymore.
And that's how the Slovaks in Czechoslovakia became their own country.