ah so youll go through the dream until you get the cutscene with the mother in the middle of the room (she'll talk to moths for a bit) and then youll be teleported in front of a fleshy staircase. instead of going up it, turn around and walk down the map! you cant miss the staircase as its part of the storyline progression ^w^
hope this helps and i hope youre having fun with the game!