There are no screws in the process except the four holding the drive to the cage.
Very easy. The most disconcerting step for a first timer is pulling the drive cage out. There is a lot of resistance at first and it tends to make one think they will either break it, or there must be a screw somewhere holding it in.
The trick is to push against the frame just below the drive cage with your thumbs and pull the drive cage out with your fingers inside the openings, fingertips facing down.