Go to the chairs and get the brown pencil hidden against one of them, use it to open the bin and get the blue key. Then click on each of the plants to get the 4 digit code in order (7528). Use the blue key to open the cabinet and click in the code. You will get a coin. Behind the sofa on the left you will find another coin.
Go to the ceiling windows, The one on the right is clickable, you can change the colors, the one on the left shows you the order. Use the wine bottles on the window shelf for the right color order. The center diamond is orange, the upper left pane is green, the opposite is blue, the one in the lower right corner green and the one opposite that in bottom left is blue. This will give you a pink key.
The last coin is by the window to the left of the front door (click on the bottom of the shades to go close up to get it.)
Now go to the front door, use the three coins and the pink key to open it.

Go to the floor by the chairs, find pencil on the side of the chair use on bin.

should get it from there