Turn right from the place where you're standing and move forward until you reach an opened door on the left side. Now, turn left and exit the room through that opened door. From here, turn left and walk in the passage till you reach a wooden wall in front of you. Now, turn right and you can see a staircase. Walk all the way down through the stairs and turn right. Now, you're facing towards a portrait. From here, turn right and move forward towards the narrow entrance. Enter into that entrance and that is the end point.