To make your arms move, you first need to connect the servo motor controller to the servos. The servo controller you are going to use for this project is a simple servo motor controller utilizing USB from Pololu, Pololu item #: 1354 available at http://www.pololu.com, which can control 18 servo motors.

Here is a picture of the unit:

Make sure you order the assembled version. This piece of hardware will turn USB commands from the Raspberry Pi Zero into signals that control your servo motors. Pololu makes a number of different versions of this controller, each able to control a certain number of servos. In this case, you may want to choose the 18-servo version so you can control all 12 servos with one controller and also add an additional servo to control the direction of a camera or sensor. You could also choose the 12-servo version. One advantage of the 18-servo controller is the ease of connecting power to the unit via screw connectors.

There...