Mount servo motor
Trace servo outline on one side of the cardboard. Make sure to leave enough room that the rotating drum and slats will be able to rotate freely.
Press servo into cutout.
Use hot glue or screws to hold the motor in place.
Make a set of 8 cardboard spacers by cutting small squares of cardboard and poking a small hole through the center.
These spacers will make it easy to set the position of the fingers so they line up with the slats inserted in the rotating drum
Position pivot point for the fingers.
Push skewer through cardboard.
Add fingers and spacers one by one.
When you're finished you should be able to spin the axle and see it rotate freely within the fingers.
Set the Slats
You can now slide some squares of cardboard into the rotating drum and test how they interact with the fingers.
Connect the Vout pad on Circuit Playground Express (CPX) to the servo's red wire, the A1 pad to the yellow wire, and the GND pad to the brown wire.
The alligator clip-to-male jumper wire connectors are great for connecting servo motors to CPX.
Your hand is now ready for some MakeCode!