Reassembling the casing goes faster, but is still tricky. What worked for me was this order:

First I attach the base panel. (Easy peasy.)

Then I dry-fit (no screws) the back panel.

Next I attached the front and side panels together with the single screw at the join between them.

Then I started with the front of the combined panels, and angled the bottom edge of the front panel into the base panel.

The right back corner is the tough part, again. You need to get the right panel's tabs into the base panel at its bottom edge, at the same time it's lined up with the back panel's tabs. Then you'll have to use a plastic spudger or flat head screwdriver to push in the side panel's flange at the top of the power cord outlet. Good luck.

After it was dry-fit, I put in all the screws for those panels. Then I attached the left side panel and the top panel with no trouble.