What part of greek play would give the BACKGROUND of the story?

In a Greek play, the background of the story is typically provided in the prologue, where a character or a chorus presents essential information about past events, characters, and the setting. This introductory section helps the audience understand the context and motivations of the characters before the main action unfolds. Additionally, the parodos, which is the entry chant of the chorus, may also provide further background information and thematic insights.