Figurative language uses words or techniques to communicate more meaning than the literal words themselves.
Carver gives the narrator a down-to-earth voice by having him use slang. An example would be his noting that his wife "sent the tapes off lickety-split." "Lickety-split" is slang for quickly. The term adds color and energy to the statement.
Carver communicates the wife's nervousness when the blind man first arrives by using repetition. She repeats the word sofa as she chatters to the blind man:
This is the sofa. We just bought this sofa two weeks ago.
Near the end of the story, when the blind man says "You’re cooking with gas now" he is using a metaphor, a form of figurative language. A metaphor is a comparison that doesn't use the words like or as. The blind man makes this comment as the narrator gets more enthusiastic in his drawing of the cathedral. By likening the narrator's action to cooking with gas he means that Robert is really pepping along, just as a pot on a gas stove might.
The narrator uses another metaphor when he tries to describe the urgency he feels about having to describe the cathedral to the blind man when he doesn't know how. He compares his feeling to:
Say my life was being threatened by an insane guy who said I had to do it or else.