Be sure of the correct dimensions of the switches. See parts list.

Print the front top silk PDF with size 100%, and use it as a drill template. 
-  Adjust the picture centered to the ALU front plate, fix it with tape,
-  Mark the holes using a center punch.
-  Drill them.
-  Check that the LEDs will fit.

           Assembling:
-  Screw the switches loosely into the ALU front plate.
-  Install resistors and diodes at the PCB front plane and
         solder these parts at the inside copper plane.
-  Solder the eight to the rest of the system connecting wires.
-  Slide the legs of the LEDs into the holes of the PCB.
      Do not solder them. The flat side on the rim is marked at the PCB.
-  Shift the switch pins into their holes on the PCB.
-  Adjust the switch nuts so, that all switch pins are equally seated into the PCB.
-  Tighten the nuts firmly.
-  Solder the switch pins at the PCB back.
-  Now slide the LEDs fully into their holes in the front plate, and solder them at the PCB back.

REM : when screwing the front plate or back plate onto the cabinet, put a little grease on the screw thread.
It will help easy screwing, and prevents damage to hole and screw.

All PCBs have printed wire connection IDs. They are the same as on the schematic diagram.