Answer:
The narrator of Geoffrey Chaucer's "Canterbury Tales" is the author himself. He met the group of pilgrims on his own way to Canterbury.
He uses the General Prologue to introduce the other pilgrims he met in the Tabard inn, thus, making it as a platform for providing the general overview of the other characters that we are to hear from.
Explanation:
Geoffrey Chaucer's "Canterbury Tales" is a collection of stories that are told by the pilgrims on their way to the pilgrimage to Canterbury. The narrator of the "Tales" is also a pilgrim whose real social status is unknown.
In the General Prologue, the narrator talks about the beginning of spring, about the April rains. This invocation to spring acts as an introduction to the whole narrative. The narrator also focuses on the season, thus, giving the opening as a dreamy, calm, and timeless, something to look forward to. Recollecting how he, by chance, came upon the other pilgrims, he reveals how he decided to be with the group of pilgrims and make it a point for him to narrate their stories, for he has "tyme and space" to tell the stories. Besides, they are all headed in the same destination, so he thought it wise to accompany them and pass their time telling each other stories.
He also uses the prologue to give an introduction, a general overview of the other pilgrims that he met in the Tabard Inn. He characterizes the pilgrims, starting from the Knight, and also introduces their social status and professions. Their appearances and behaviors were also looked at or commented on by him. He focuses on the purpose of taking the pilgrimage, what their backgrounds are, and also what made them come for the pilgrimage.
Thus, the prologue acts as a precursor, an introduction for what the future narrative will be about and also gives us the platform to get acquainted with them before they all start narrating their stories one by one.