Move the foot pedal or hand dial so the needle is down as low as it will go.
Locate the small knob near the top of the needle. Twist the knob loose until the needle releases from the unit.
Insert your new needle. Sewing machine needles are universal so one side is always flat and the rest is in a semi-circle shape. Slip the needle into position and twist until the shape matches up and slides into the needle holder. Twist the knob until the sewing machine needle locks tightly into place.