Locate the clip cord input on the face of the tattoo machine. This is normally a single prong outlet where the end of the clip cord is inserted.
Insert the clip cord into the power supply. Firmly seat the cord so it won't fall out and cut off the power when you move the gun.
Bend the U-shaped end of the clip cord gently and seat each prong in the contact points above the magnetic coils of the tattoo gun. Secure the connection. The cord must be able to move without slipping out of the machine.