Use arrow keys to move, pgup to look up, pgdn to look down. And space to reset the camera.

Go to the closet and open the closetdoor with the doorknob.
Look down to the floor and get the key.
Go to the front door and right click your mouse to go the inventory. Chose the key from your inventory.
Click on the door and use the key. Do not click on use, but on key.
Now the door is open and you can go outside. Take a peak on the animated milkshape object that is around somewhere.