Calculator no longer working after opening it up

Calculator no longer working after opening it up

Hello I tried to clean the keyboards of my calculator by taking apart according to YouTube but when I put it back together the screen just goes in and out sometimes and shows a lot of lines but nothing clear. I remember I had to pull back the thin metal or aluminum sheet to get to the keys but I put it back. Should there be anything specific to look at when I open it to see why it’s doing that?