Next you will want to connect the input to the loop receiver. You can connect to any open input on the receiver, I used the Aux input, but you could use any input except Phono which doesn't allow line level inputs. Also the loop system will be in Mono (not stereo) so pick either the Left or Right connector to use, and remember which one you chose for later. Here I plugged it into the Right-Aux input.
The other end of the cable should be plugged into the audio output of your TV, the audio output of your VCR, or the "monitor," "pre-out," or other line level output on a primary reciever. You could also split a signal from an audio output already going to the primary receiver for this purpose.