How to separate: Use a sharp and thin breakaway/razor/stanley knife to separate the frames. Use gloves and cut away from your fingers. The knife has a tendency to get stuck but then jump ahead as the layers separate so be careful! Inspect and cut away leftover pieces on the top and bottom side. Attach the cover piece (the visor does not work without it) by aligning the snap features and pressing firmly. The flat part of the cover goes on the top side of the frame, hooks on the tapered frame side. Tested the design using PETG Use the 3 piece test file to evaluate before committing to the 22 piece stack. You may nest the two parts, but optimal settings is different so separate printing is recommended. I have included small mouse ears which is probably sufficient if you have good first layer adhesion. If you are uncertain do use a brim to ensure a successful print.