Solder LED Strip
Cut a high density Neopixel strip to 61 pixels and use silicone ribbon cable to help keep the wires bundled.
Tin the pads on the NeoPixel strip and solder wires to the data and power and ground pads.
Tin two pins on the slide switch. Add heat shrink to each wire and then solder to each pin on the slide switch.
Use the side of the solder iron to heat and shrink the connections.
Solder quick connects
Use one of the ground connections close to the prototyping area to solder the quick connect wires for the button. The other wire connects to pin 5.
Orient the Feather board so the USB connection is facing the cut out on the case.
Use four M2.5 x 5mm long screws to secure the Feather board to the standoffs on the case.
Mount LED strip
Pass the LED strip wires through the cutoff on the inside of the case. Wrap the LED strip along the inner wall of the case.
Use kapton tape to cover the pads on the end of the NeoPixel strip so the pads doesn't short the circuit.
Mount slide switch
Place the switch to the middle position and then angle the whole slide switch so it can press fit between the three walls on the case.
Arrange the printed diffuser with the bigger lip face up. Gently bend the diffuser so it can press fit over the LED strip.
Plug in Battery
Plug in the JST extension cable to the Feather board and then attach the battery. Use foam tape to secure the battery to the case.
Use pliers to slightly bend the connections to fit inside the case.
Attach the printed button shelf to the button.
Align the button with the crown icon as shown. Pass the button at an angle and then twist clockwise to mount the button.
Attach the quick connect wires to the button. The wires attach to the connections close the points on the crown icon.
Match the cut out on the lid to the slide switch. Use slight force to press fit each nub around the lid on to the case.