Using the Klein NCVT - 5A is easy. First, make sure the two AAA batteries are properly installed. Turn on the tester and select the appropriate voltage range (12 - 1000V AC for low - voltage systems or 70 - 1000V AC for standard electrical systems). To use the laser pointer, just activate it as needed. When you bring the tester close to a possible voltage source, it will give you visual and audible signals if voltage is present. Remember, the higher the voltage or the closer you are to the source, the faster the beeping. As for maintenance, keep the tool clean and dry. Avoid dropping it, although it can handle a 9.9 - foot fall. When the battery life runs low, replace the AAA batteries. The auto - power - off feature helps conserve battery, but if you're done using the tool, you can also manually turn it off. And always follow safety guidelines as it has a CAT IV 1000V safety rating.