The enclosure is comprised of seven (7) laser-cut acrylic pieces. Peel the paper backing from the acrylic case pieces. Some people use a razor blade as a scraper to get this started, but a fingernail at a corner is usually sufficient and won’t gouge the plastic.
After peeling, the parts may have a little bit of paper soot on them from laser cutting. Wiping off may suffice, or they can be washed with soap and water…but be absolutely certain that everything is completely dry before assembling components in the case!