I will explain basically how I built my system, you can adapt the design to fit your needs. Below is the diagram of the room, further explanation follows.
First, as the name implies, it is a loop of wire, and in general the signal is picked up only when the person is inside the loop, however depending on the power of your amplifier, it may work for a distance outside of the loop. Since the viewing position for the TV was basically the couches, and not wanting a wire running across the floor to trip on, I chose to loop only the couches. I chose to simply lay the wire in the gaps between cushions to hold it in place, I will see how it holds up over time. I will explain the kind of wire I used in a moment.
I have a reciever setup for a full Dolby Digital (5 speaker + Sub Woofer) surround sound system, so I chose to add a second receiver for the loop system. If you only want to use one receiver you can, but using two allows independent control over the volume going to the speakers and volume going to the loop system. The receiver I used for the loop system can put out 50 watts per channel which is plenty for a small room. Larger sizes - as big as a full theater - can be achieved by adding more power.
You will want to place the Loop receiver near the couch for easy adjustment. I ran an RCA cable from the center channel Pre-Out from my main receiver. I chose center because in a surround sound system, 70% of the sound and almost all the voice comes from that channel. The other channels are mainly for directional sound and effects.