Complex sentence: James, who worked at a sweatshop nearby on Canal Street and dreaded going home after school, visited Beauford--at 181 Greene Street--who became a mentor to James, his first realization that a black person could be an artist.
Split into simpler sentences: James, who worked at a sweatshop nearby on Canal Street and dreaded going home after school, visited Beauford at 181 Greene Street. He became a mentor to Baldwin, and Beauford's influence brought him to his first realization that a black person could be an artist.