There should be an "Audio Ouput" along the rear of the TV. All you would need to do is use an RCA (red and white) cable to connect from the TV to the audio input on the receiver. I can't say how you should connect your sound system, but all you would need to connect the TV to the external sound receiver would be that RCA cable.
I want to connect external speakers to my new Samsung TV. I think that I need an amplifier and imagine that two leads go from TV ouput to amplfier and then two leads from this to speakers. But I'm unsure of exactly what the TV output sockets are. Or would I be better getting a Home Cinema package which I think has it s own amp ?