I've had mine off many times: If you look very carefully around the sides of the cap there's a small cutout on one long edge into which you insert a small screwdriver and carefully lever up. The cap can go back 2 ways and often the cutout is at the top in front of the screen where you can't see it. If you damage a cap and the moulded clip no longer holds it you can put it back with Blue Tack
The screws from memory are black self tappers which you can measure and get off Ebay or elsewhere.
The screws from memory are black self tappers which you can measure and get off Ebay or elsewhere.