In Scene 1, the stage direction is very important for the audience. Tennessee Williams is very specific about lighting, darkness, and music

From the text:

At the rise of the curtain, the audience is faced with the dark, grim rear wall of the Wingfield tenement. This building is fianked on both sides by dark, narrow alleys which run into murky canyons of tangled clotheslines, garbage cans, and the sinister latticework of neighboring fire escapes. It is up and down these side alleys that exterior entrances and exits are made during the play. At the end of Tom's opening commentary, the dark tenement wall slowly becomes transparent and reveals the interior of the ground-floor Wingfield apartment.