The DC motor rotates a shaft when it receives a signal. The more signal it receives, the faster the motor will spin. A switch on the board lets you choose which direction the motor spins. CW spins clockwise and CCW spins counterclockwise. When the switch is in VAR (variable) mode, the amount of signal the motor receives from previous Bits allows you to control the speed and direction (clockwise or counterclockwise) of its motion. In this mode, using an input like a slide dimmer makes steering easy!