Start by placing and soldering the components on the front of the board:
LT1054 and 1N4001 diode at the top center, potentiometers, trim pots and slide switches as in picture.
Now it is time to place the connectors on the back of the board.
Remove the lateral leg of the DC connector and solder it, carefully aligning it to the pcb.
Place and solder the 1/4" jacks, you won't need the nuts on those.
Cut three ~10cm wires (not included) and solder the SPDT stomp switch. There is no orientation so just be careful that the central hole of the footprint matches the central pin of the switch.
Merge the translucent green board with the top part of the enclosure. Fix the screws to the hex spacers.
Now merge the circuit board and the enclosure and carefully tight all the potentiometers nuts.
Put two plastic feet on the upper two holes on the bottom part of the enclosure (see picture) and tighten the two self locking nuts.
Put on the last screws on the bottom plus the other two plastic feet. Done!