Who does the narrator follow at the start of the story? Where does she go each week? What does she buy? Where does she sit after?

The narrator follows a woman she refers to as the Woman in the Purple Skirt. The Woman goes to the same bakery each week and purchases a cream bun. The Woman then goes to the park and sits on the same bench, which the narrator calls The Woman in the Purple Skirt's Exclusively Reserved Seat.