We always recommend glass over Plexiglas, plastic, etc. which will only scratch with age and cleaning. The 4 corner posts are attached by 4 top and 4 bottom screws that go down through the top frame and up through the bottom frame to hold the display together. The top glass just lays in the recessed area in the top frame. The case baseboard fits in the bottom of the bottom frame and the metal clips twist and can be tightened to hold the baseboard. Your piece can be attached to the case baseboard and the case lowered over it, or you can put items into the case through the top glass opening.
Some people prefer no stain at all, just the natural wood color especially on cherry.
Additionally, they are perhaps less apt to drip or clog a glass track than thicker brush-on varnishes and thicker coatings. If you need additional information, we welcome the opportunity to be of service. We at Copperfields enjoy and appreciate fine craftsmanship and hope our display case will also give you years of pleasure and protection for your prized piece. We have many repeat customers and appreciate your business and comments and welcome the opportunity to be of service with your future display needs.