In one sentence, describe what the following article is about:

Do not touch the metal probes while connecting them to a circuit. If the insulation looks worn or torn, wear electrically insulated gloves or purchase replacement leads. The two metal probes should never touch each other while they are connected to a circuit, or severe sparking could result. Test circuits for voltage by attaching the leads in parallel. In other words, you'll touch the probes to two points an already-closed circuit, with current running through it.  On a battery, touch the black lead to the negative terminal. In a wall outlet, touch the black lead into the neutral hole, which in the US is the larger vertical hole, or the vertical hole on the left. Whenever possible, let go of the black test lead before moving on. Many black probes have a small plastic bump that can stick into an outlet. This will complete the parallel circuit and cause the meter to display the voltage.  On a battery, touch the red lead to the positive terminal. In a wall outlet, fit the red lead into the "hot" hole – in the US, this is the smaller, vertical or the vertical hole on the right. Immediately raise the range to a higher voltage setting if you get one of the following results, before your device is damaged:  Your digital display reads "OL," "overload," or "1." Note that "1V" is a real reading, and nothing to worry about. Your analog needle shoots to the other side of the scale. You may need to make adjustments if a digital voltmeter display reads 0V or nothing at all, or if an analog voltmeter's needle has barely moved. If there is still no reading, try the following in order:  Make sure the test probes are both connected to the circuit. If you are measuring a DC circuit and get no result, look for a small knob or switch on your device labeled DC+ and DC- and move it to the other position. If your device does not have this option, reverse the positions of the black and red probes. Reduce the range by one setting. Repeat if necessary until you get a real reading. A digital voltmeter will clearly display the voltage on its electronic screen. An analog voltmeter is a little more complicated, but not too tough once you learn the ropes. Continue reading for instructions.

Summary:
Hold the probes safely. Touch the black test lead to one part of the circuit. Touch the red test lead to another point on the circuit. Raise the range if you get an overload reading. Adjust the voltmeter if necessary. Read the voltmeter.