Using the D'Addario DIY Solderless Cable Tester is simple. First, make sure the CR2032 battery is properly installed. Then, connect the 1/4” mono audio cable or 2.1mm power cable you want to test to the tester. It will quickly tell you if there are proper connections or shorts. Refer to the reference guide on the back of the unit if you're unsure about the results. When using the DIY Cable Kit to make your own cables, firmly push the plugs onto the cable and then tighten the screw on the side of the plug. Measure the cable easily with the foot - markings. For maintenance, keep the tester and cables in a dry place. If the tester doesn't work, check the battery. Also, avoid bending the cables too sharply to prevent damage.