Peel the protective film off of both sides of each panel.
Now, lay each panel into place inside the lid. You can use tape or hot glue to secure them once they are lined up properly. Check from the top of the lid to make sure there aren't any spaces on the sides through which to peek.
Place the Hall effect sensor into a corner of the lid and secure it with tape. Make sure point the face of the sensor that reacts to the magnet outward.
Now, use gaffer's tape to secure the wiring, battery, and the Trinket/charger combo in place. You can leave enough slack so that you can plug in a USB cable to charge the battery.
And now, your Shutterglass Chamber is complete! Screw the lid back onto the hinges, fill the chambers with artifacts and clues, and then use the magnet for the dramatic reveal!