The Hunger Games is set in Panem, a fictional future North America. Panem is a dystopia, which means that nothing really works very well -- it's dysfunctional. According to Fandom, "The name Panem derives from the Latin phrase panem et circenses, which literally translates into 'bread and circuses'. The phrase itself is used to describe entertainment used to distract public attention from more important matters. Furthermore, by the government providing ample food and entertainment, the citizens would give up their political rights."
Katniss Everdeen is a hunter. She uses a bow and arrow. She basically hunts and barters for the family food. She is very good at it. She and her family are on the lower level of society. The first chapter is a cool character study.
The Hunger Games have been around for a long time; it is a tradition. The contestants compete -- fight -- for food, survival, etc. One person is chosen from each District. Katnip's sister, Prim, is chosen to represent her district. Enraged by the unfair nature of the choice (Prim is only 12 years old), Katnip volunteers for The Games.