Select the voltage on the back of your power supply. Many power supplies are designed for international used and have a variable voltage switch. Make sure your machine is set to the appropriate voltage for your country before beginning.
Connect the power cord to your power supply and plug the power supply into a standard electrical socket. Place the power supply on a clean, flat surface with plenty of clear space--do not place anything on top of or against the power supply.
Attach the clip cord to the tattoo machine and then attach the clip cord to the appropriate socket on the power supply.
Attach the foot pedal of the machine to the power supply and place the pedal on the floor. Test the connection by pressing the foot pedal and observing the needle.
Tune the power supply using the voltage knob. The recommended settings vary based on the type of tattooing--generally a setting of between 6.5 to 7.5 volts is recommended for outlining and line work. For shading work, set the voltage between 7.5 and 9.5.