They are used just like a regular hobby servo. You will need an external power supply for the servos. Arduinos just can't supply enough current for a servo (especially one under load) nor can they supply 6V. A 4 AA battery pack is a good choice for power. Connect the + of the battery to the + of the servo, the control line to an Arduino pin and the - (ground) of the battery to the - (ground) of the servo and Arduino ground.
The Servo library that is included with the Arduino IDE makes using servos easy.