i think i can help.
when you click on a computer you see colours on the screens. these colours represent which bookcases they raise.
the 3 on the front are red,blue and yellow
the ones in the back are orange, green, white and purple.
one hint i can give with certainity is to get the sides as high as possible and the middle(blue) low.
P.S. atleast that's what worked for me in ep 13