What does it mean when people refer to Hamlet’s hiring of the players in Act IV as “the play within a play?” What is Hamlet using these players to do?

Read the passage from the "general prologue" to the canterbury tales and answer the question. at table she had been well taught withal, and never from her lips let morsels fall, nor dipped her fingers deep in sauce, but ate with so much care the food upon her plate that never driblet fell upon her breast. in courtesy she had delight and zest. her upper lip was always wiped so clean that in her cup was no iota seen of grease, when she had drunk her draught of wine. what can we infer is chaucer's point in including this description of the prioress? to illustrate her commendable manners. to distinguish her from less courteous pilgrims. to show her discomfort at being outside her convent. to emphasize her lack of religious priority