You need a green table and two boxes, invade the Neighbor’s House through the front door and, place the green table on the floor near the front door and place two boxes on the green table, then jump on the table carefully to the boxes do not fall, and move the camera up (Dragging the Mouse) and Press E to activate the Lever (Open) and look to the right and Hold E to get the yellow key and use it on the second floor in a door with a yellow padlock.
How to Get the Yellow Key?
