Okay kiddo, so in 1939, there was a group in Slovakia called the Communist Party. They believed that everyone should share everything equally and that the government should control everything to make sure that happened. They called themselves Marxist-Leninists and wanted to create a society without rich or poor people.
However, the government at the time didn't like this idea very much. They thought that the communist party would try to overthrow them and take control of the country. So they made it illegal to be a member of the communist party and many members were arrested or went into hiding.
Despite this, the communist party continued to operate underground and try to spread their message to the people of Slovakia. They published newspapers and pamphlets and tried to organize unions and protests. But it was a very difficult time for them, and they faced a lot of opposition from the government and other groups who didn't agree with their ideas.
Eventually, in 1945 after World War II ended, the communist party gained more power and was able to become a legal political party in Slovakia. They were able to participate in elections and even became the ruling party in the country for a while.
So that's a brief explanation of the Communist Party of Slovakia in 1939, and how they faced challenges and ultimately gained some power in the country.