Short answers, pulled from the story.
Snorri Sturluson, an Icelandic scholar and lawspeaker, wrote or compiled the Prose Edda around 1220. A paragraph in Codex Upsaliensis dated to the first quarter of the 14th century explicitly names him as the writer.
Seven manuscripts of the Prose Edda have survived into the present day spanning from the early 1300s to the 1600s. Six copies date back to the medieval period while another emerged during the 17th century.
The Prologue presents a Christian reinterpretation of Norse gods by describing them as human Trojan warriors who fled Troy after its fall. This narrative parallels Virgil's Aeneid while adapting ancient myths for medieval audiences.
Gylfaginning describes how ice and fire met at the beginning to create Ymir the first giant and how Odin Vili and Ve shaped the earth from his body. The narrative ends with a new green world rising from the ashes of destruction after Ragnarök when wolves swallow the sun.
Skáldskaparmál contains approximately 50,000 words dedicated to lists of kennings and heiti used in skaldic verse. It includes systematic lists explaining how poets refer to people places and things metaphorically along with origin stories behind many expressions.