Just connect either set of the outputs to the CD inputs on the receiver and turn on the receiver and FryKleaner. If you have some 8R resistors to load the receiver with instead of speakers that would be nice, so you don't have to listen to it.
As for level, I don't think you need to run the amp real hard to break it in. Perhaps hook up the speakers and advance the volume to a reasonable l listening level then shut it down and connect some load resistors and let it cook for a few days. If you turn the power up too high it could overheat (both the amp and the load) and that would certainly not be good.
I would try the middle (0dB) setting on the FryKleaner. This should provide a good strong signal without overloading the preamp section.