start with the SMD Parts: 2 x diode on controlboard
assembly the potted PCB
assembly the controlboard, SW input pin 2 must be connected to SW output pin 2 (see picture)
mount all spacers for frontpanel and potted module, the 4x 12mm spacer are between controlboard and potted module, the other 4x 12mm spacer between potted pcb and DIYSYNTH cover pcb.