How do you beat pentagonal room

Ok well to get the silver key you go to the computer desk and click on the crayons, then click on the swamp green crayon, there it is. For the crystals 1.) you go to the blind, pull the left string and then the right string, solve the puzzle and get the crystal. 2.) go to the door and click on the poster, put in numbers that add up to the number above them.
Sorry that's as far as i got but i hope this helps :-(