Remove the headshell from the stylus arm. The headshell is the plastic end of the arm. Raise the arm slightly. Look under the arm. You will see two wires, one red, one blue. Unplug them with your fingers.
Unscrew and remove the two small screws in the arm. The screws are next to where the wires came off. Gently pull the headshell off the arm with your fingers. The headshell is the end of the arm that holds the stylus and needle.
Hold the overhang gauge down firmly with your fingers. Snap the headshell onto the end of the overhang gauge. The end of the overhang gauge looks like the end of the stylus arm. It should snap on lightly; you don't need to screw it on.
Look straight down at the overhang gauge from overhead. Look at the gauge from the front. There is a line cut into the bottom of the overhang gauge that represents the groove on a record. The needle on the stylus should line up exactly with the groove. If it doesn't, turn the screw on top of the headshell directly above the stylus. It will move the needle. Turn the screw in the direction needed until the needle aligns with the line in the gauge. When the needle aligns with the screw, the overhang is correct.
Pull the headshell off the gauge. Screw the headshell back onto the stylus arm. The blue wire attaches to the blue post, the red wire to the red post. Your turntable is ready to play records.