When you use a receiver with an outboard amp, the receiver's amps are bypassed. On the back of your receiver there are pre-outs. RCA cables are run from the pre-outs to the inputs on the amp therefore bypassing those amps in the receiver. Then you must connect speaker wire to the amps binding posts and run to speakers. Your amp will be putting out 120w/channel. The unused amps in the receiver will sit dormant if there is no channel to send it to. Many people use only a 2 channel or 3 channel outboard amp to power the fronts or front three(L-C-R). In these cases, only those channels are bypassed in the receiver and the receiver handles the rest.
Bill
Bill