Snap the circuit like this:
Battery-Power-Wire-Sound Trigger-Wire-Bright LED-Wire-Bright LED-Wire-Bright LED-Wire-Bright LED-Wire-DC Motor
The box is constructed assembling the parts you cut with the laser cutter (the file is attached for you) with Elmer's style glue (or any craft glue). Add the ring piece on top as shown in the pictures, this will hold the screen concentric in the box. The front side is the piece with the round hole (for the sound trigger), the back side has a bigger slot so you can turn the power on and off, as well as change the battery. There are four small circles that under the base to lift the box a little from the floor. Be patient and let it dry!
The horse stencil is also laser cut with the attached file. Once it's done, wrap the stencil strip around the 3D printed motor wheel (file also attached) with double side tape. Make sure the D-cut for the shaft of the motor is facing down
Build a central squared post where the bits will be held. Balsa wood is probably the easiest way, so you can screw it in the center of the base of the box. If you build a T-shaped surface on top, it will help the positioning of the motor with its shaft centered in the box (see pictures)
Assemble the bits in the box. The battery and power sit flat in the base. The Sound Trigger sits sideways, fixed to the inner side of the front face. Make sure the sound sensor sits concentric with the front hole. Attach one Bright LED in every face of the pole with rubber bands and the DC motor the same way. Make sure the shaft is centered with the round opening of the box.
Introduce the wheel with stencil in the shaft of the motor (Both are D-shaped so they don't spin into each other)
Cut the screen top out of the foam core board, the same size of the wood ring you glued in the top of the box
Wrap the japanese fiber paper (or any medium thickness paper, around 85g) with double side tape into the foam core top.
Introduce this screen you just built on top of the box, concentric with the center of the box.
Turn on the power, and work your voice magic. You can clap, you can tap in the box, any sound trick will bring the carrousel to life. If you are in a noisy environment remember that you can adjust the sensitivity of the sound trigger with a little purple screwdriver so the magic is not revealed before the expected...