In the subsystem, create the actuator (piston, talon, etc.). eg.
private CANTalon lifterMotor = new CANTalon(Ports.ARM_CIM);

Then, create a function that does what you want. eg.
public void moveLifter(double speed) {
    ...
}


If you need to get input, create a small function that returns the value. eg.
public double getCurrentHeight() {
    return armNDOF.getHeight(SensorEnum.ARM_NINE_DEGREES_OF_FREEDOM);
}