Do this on a well-lit, flat surface. Use clear tape to hold the loose screws in order of reassembly on a piece of paper or on the table while you work.

4 on top row, 3 on middle row. 1 middle row screw is shorter, black.

Pry up gently on the left and right as shown in the photo - left and right middle edges - to get the back off if it sticks. Be gentle and careful because there is a motherboard under the black cover.

Back cover isn't held in place with tons of glue and such, so it should come off easily prying gently on the two locations noted, if it doesn't release by pulling off with just your fingers.