Start with the base. This is just a piece with a square slot large enough to hold the motor (with a hole out the back for wires). Connect the power supply to the motor and place the motor in the base.
Fasten the motor to the lid with two screws.
Fasten the lid to the base with two screws.
Fasten the base to the top of the tree with tie wraps.
My wife made a Santa from clay. I scanned and printed Santa in plastic, then she painted him so that he could be a colorful character.
Taking the "T" piece and fishing line, I attached Santa.
Press fit the arm to the motor shaft and plug it in.