One common configuration is called 5.1 surround sound. This configuration uses 5 speakers: two front (R and L), two rear (R and L), and one front center. The '.1' corresponds to a subwoofer for increased low-end response. (A similar configuration -- 5.2 -- supports two subwoofers for a stereo feel.)
You'll need a 'surround sound receiver' from your favorite consumer electronics store. Around 300 W should suffice -- most of the power supplies the sub-woofer. 5.2 receivers tend to be in the 700 W arena due to the double low-end.
Any decent receiver these days will allow you to adjust the volume for each channel so you can 'tune' the room. You'll have to make sure the receiver can drive your particular set -- i.e. make sure it can drive your 4 Ohm KLH speakers.
Make sure any receiver you buy can interface with your TV. It appears that your model can pretty much only output HDMI or optical audio.
You'll also need some speaker wire to connect your receiver with the wall connectors. You can put your solder skills to the test and solder some banana jacks to one end of speaker wire, or look for ready-made cables.
All of your speakers are passive, meaning that they do not require their own power. (Active speakers have their own integrated amplifier, and have input power inlets and switches.).
The front Yamaha with the cut wire looks like it can be repaired with simple wire nuts. Make sure to connect the same colored wires together -- the white with the white and copper color with copper color. Wrap some electrical tape over the nuts, too.
The easier way to tell which wall terminals go to which speaker is to hook up your amplifier (receiver) to each terminal pair (red and black) one-by-one. Logically, the top-left pair corresponds to the front-left speaker, bottom-left pair to the rear-left speaker, and so on. But one can never assume.