Attach five 12mm M2.5 stand-offs with M2.5 screws into the skull's mounting holes in its nose and mouth.

Attach an 8mm M2.5 stand-off with an M2.5 screw into the 1/4 perma proto's mounting hole located between the socket headers.

Then, plug the QT Py RP2040 into the socket headers.

Slot the 1/4 perma proto and MCP4725 STEMMA board onto the mounted stand-offs. The two audio jacks will slot into the skull's eyes.

Secure the boards to the stand-offs with five 8mm M2.5 stand-offs.

Secure the back plate to the stand-offs with M2.5 screws. That completes the assembly!