The red arrow shows where a screw is located which holds the back chassis in place. Remove it with your screwdriver and set it in separate container. Since this Lenovo x200 is the tablet model we to swing the LCD screen like in the picture below.

This will make it easier for us to remove the chassis plate because the LCD is in the way of removing the chassis plate.Take your credit card slide it underneath the plastic chassis to loosen the plate. Gently lift around the plate with the credit card and now slide the plate out from underneath the LCD screen.