Summarize:

To build a simple circuit, you will need a power source, 2 insulated wires, a light bulb, and a light bulb holder. A power source can be any type of battery or battery pack. The rest of the materials can be found at your local hardware store.  When choosing a light bulb, find one that is around 15-25 volts so a single battery can power them. To simplify the wire attachment process, use a battery snap with wires pre-attached and a 9-volt battery or battery pack. In order for your circuit to work properly, the wires need to be totally exposed so you must strip the ends. Using wire strippers, remove about 1 inch (2.5 cm) of the insulation from the ends of each wire.  If you don’t have wire strippers, you can carefully use scissors to cut off the insulation. Be careful not to cut all the way through the wire. Depending on the type of batteries you are using, you may be able to skip this step. If you are using multiple batteries, you will need a power pack to hold the batteries. Push each battery in by the side taking care to put the positive and negative ends in the correct orientation. The wires will be conducting your electric current from the batteries to the light bulb. The easiest way to attach the wires is to use electrical tape. Attach the end of one wire to one side of the battery, making sure that the wire maintains contact with the metal of the battery. Repeat with the other wire on the other side of the battery.  Alternatively, if you are using a battery snap, snap the end onto the end of a 9-volt battery or the battery pack. Use caution while building your circuit. Although unlikely, it is possible to get a very small shock if you touch the wire directly while attached to the battery. You can avoid this by only touching the insulated part of the wire or removing the batteries until you install the light bulb. Take the exposed metal end of each wire and bend it into a U-shape. Loosen each screw on the light bulb holder just enough to slip the U-shape of the wire around the screw. Each wire will be attached to its own screw. Tighten the screw, ensuring that the metal of the wires remains in contact with the screw. Screw the light bulb into its holder until it is tight. If your circuit is hooked up properly, the bulb should light up when fully screwed into its socket.  Light bulbs can heat up quickly so be careful when installing and removing the bulb. If the bulb doesn’t light, check to make sure the wires are touching the ends of the battery and in contact with the metal of the screws.
Gather the necessary materials. Strip the ends of the insulated wires. Install batteries into the battery pack. Attach your wires to the battery pack. Fasten the other end of the wire to the metal screw of the bulb holder. Test your circuit.