Start with all parts and tools layed out infront of you.
Name all the parts
* Lower and upper housing
* Bell Crank
* lower and upper crank shaft
* lower and upper linkage
* Servo + its screws
* 8x 2x12mm pins
* 4x M3x10 screws

* 2mm drill bit
* Vise
* Screwdriver
* FDM 3D-Printer

Position servo
Install servo
Orient and push on lower crank
Connect linkage and bell crank
Insert linkage and bell crank while pushing on linkage to crankshaft
Push on upper crank 
Push in Contact pin to upper housing
Push in crank bearing pin to upper housing
Add upper housing

Show simple connection to RPi pico
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