Wiring your home for multiple sets of speakers connected to a single amplifier or receiver is a fairly simple way to achieve a multi-room, whole-house audio system. A system like this does have some limitations. For example, your volume control is limited to the volume set in the main room. You can correct this problem by adding a speaker volume control in the rooms you've added speakers to.
Decide on the location for your volume control. You'll want to locate it in a spot that is easy to get to so you can quickly and easily adjust the volume. If you already have existing runs of speaker wire, locating the volume control along the speaker wire run will simplify installation.
Identify your speaker wires. In a stereo speaker set-up, you'll typically have two cables (the right and left speakers), each with two wire leads (the positive and negative).
Cut the right speaker cable leads with a pair of wire cutters. Mark or note to yourself which of the cut ends is on the speaker end, and which is on the amplifier end. Strip 3/8 to 1/2 inch of insulation from each of the leads on each side of the cut cable.
Loosen the speaker wire screw terminals of the volume control, so that openings appear that are large enough for you to slide the bare ends of the wires into. This usually requires a Phillips screwdriver.
Slide the bare ends of the speaker wire leading to the right speaker into the terminals marked "speaker" on the volume control. Slide the positive lead into the "+" terminal, and the negative lead into the "-" terminal. Tighten the terminals to hold the wires securely.
Slide the bare ends of the speaker wire leading to the right amplifier channel into the terminals marked "amp" on the volume control. Slide the positive lead into the "+" terminal, and the negative lead into the "-" terminal. Tighten the terminals to hold the wires securely.
Repeat Steps 3 through 6 to connect the left side speaker wires into the volume control, and tighten the screw terminals to secure the wires.