Some case pieces are reversible and can be flipped over and installed either way, while others have a specific orientation. You’ve already been acquainted with a couple of these pieces during the soldering stage. Let’s assign names to the rest of these parts so we can refer to them in these directions:
The bottom piece is scored on one side, with an outline showing the placement and orientation of the Raspberry Pi board.
Push out the laser cut holes and mount the Raspberry Pi Board to the bottom plate using the included plastic #4-40 screws
The parts baggie included with the thermal printer contains two triangle-shaped brackets and two long screws. These will hold the printer inside the case.
Note the location of the paper feed button. This should be oriented toward the BACK of the printer.
Being mindful of the wires and other attached components, slide the thermal printer through the large slot on the top case piece, with the feed button toward the BACK (the silver button is toward the front).
Set the printer and top piece face-down and insert the two brackets and screws. Use a small screwdriver to secure these in place. Use gentle pressure! Cranking these down tightly can crack the case.