It looks like you somehow pulled the keyboard layers apart. Those plastic tabs need to be pushed in towards the case. Then that metal layer pried up.
You do this by starting from one corner. Depress a tab and pry up. The keyboard will only budge a little. This just need to be enough so that tab get held back by the keyboard or the keyboard clears. You then work along to each successive tab.
The best tools for this are plastic spudgers. You can use bladed screwdrivers or even a knife. It's just hard metal will likely cause cosmetic damage.
Hopefully the keyboard isn't ruined.
View: https://imgur.com/a/zsOtA0N