Screen wont turn on after replacement

I replaced my macbook air screen. Took off the back portion disconnected the fan and everything and then removed the screen as described in the ifixit guide. When I attached the new screen and put all the parts together, the screen wont work. I thought maybe it was defective and put the old screen back on but that one wont turn on either. The computer turns on because I hear the chime but nothing shows on the screen. What did I do wrong?I replaced my macbook air screen. Took off the back portion disconnected the fan and everything and then removed the screen as described in the ifixit guide. When I attached the new screen and put all the parts together, the screen wont work. I thought maybe it was defective and put the old screen back on but that one wont turn on either. The computer turns on because I hear the chime but nothing shows on the screen. What did I do wrong?