I just looked at the build doc so no pics to give.
If you are using the buffered out, the input isn't switches. It goes to the PCB. Only 2 poles will be used. Output and led.
Your output jack will be a center lug. BO and OUT to top and bottom lugs.
On another pole, gnd center lug. L- to top or bottom(whichever side OUT is wired too)
If you want to get fancy, you could use the third pole to ground the output but it's not really necessary.
Unless you're running this before any other buffers and the rest of your chain is true byoass, I would just ignore the buffer and wire it true bypass. In that case, Ignore BO and wire like a standard 4 wire true bypass, BO unpopulated