Start by assembling the display Featherwing, but use the short male headers instead of the regular headers that come with the wing.
Solder the short female headers on the top of the Feather. This will let the display clip onto the Feather with a minimum of space between them, allowing it to fit into the designed case.
Place the PowerBoost as shown: slide the USB connector out the hole in the side of the body, and slide it onto the two rear pegs.
Place the capacitor as shown (it's top against the opposite side of the body). This will position it clear of the LiDAR unit. Clip its leads where they meet the center power pads of the PowerBoost. Pay close attention to the polarity of the capacitor and match it's negative side to the ground/- power pad. Clip the leads and solder them to the power pads.
Solder the power leads from the LiDAR wiring harness (red is +, black is -) to the outer power and ground pads of the PowerBoost. The power and ground lines can be trimmed some but take care not to make them too short.
Connect two wires to the side power and ground pads. These will go to the Feather and should be fairly long to allow assembly later. 10 cm (4 in) is fine.
The I2C lines on the LiDAR harness shouldn't be trimmed much; they similarly need to be 10 cm (4 in). These are too short in the photo and unfortunately the LiDAR only comes with one harness [the author ended up trimming them all the way back and adding silicon wires to get the required length].
Attach the power and I2C lines (blue is SDA, green is SCL) to the Feather. This can be done by soldering to the corresponding pins on the back or the Feather (power to the USB pin).
With the PowerBoost still in place, a drop of superglue can be placed in each to its mounting holes to secure it in place.
Now for some soldering finesse. Slide the switch in from the outside until it is touching the side of the PowerBoost.
The switch's pins should line up with Vs, EN, and GND pads. Trim them so the just reach the pads and solder them in place.
The final step for the PowerBoost is to plug the battery into the battery connector.
Put the LiDAR unit in place, making sure that the battery wires go around the PowerBoost side, and the rest go around the other side. The connector on the LiDAR unit should be visible as shown.
Slide one of the dividers into the guide immediately behind the LiDAR unit. Verify that the notches are along the top edge of the divider, and that the small notch is near the side where the battery cable is.
Carefully place the Feather in place by sliding the LED display into the rectangular opening in the front of the body. Ensure that the decimal points are at the bottom. The Feather's battery connector should be visible. After this step the Feather's USB connector is not accessible so it should be programmed prior to this step (although you can easily undo a few steps to extract the feather if needed).
Slide the second divider into place immediately behind the Feather. If you cut the wires to the Feather too short, this is when you'll find out.
Slide the battery into place between the two dividers.
Finally, plug the LiDAR wiring harness plug into its connector.
Route the battery, Feather power, and LiDAR I2C lines into their respective notches and carefully put the cover in place, securing it with 4 M3 bolts. Using heated M3 inserts in the body holes is recommended as shown in the above photos.
Turn the switch on and you should soon see a distance reading. It can take a short while for the unit to calibrate and the reading to settle.