It appears the PS48 is specifically designed to use an Bose outboard amp to power the speakers. So if you want to use your 301 instead of the speakers they give you, plug the 301 into the outboard amp, L+R?
I notice the Bose outboard amp speakers connection maybe of a different connector/cable type, if so, you have to purchase some kind of adapters or make your own cables. Is no rocket science, + to +, - to -.
At first glance, this PS48 seems to power tinny cube speakers, are you sure the 301 is matched for this unit? Would be kinda of weird to put truck tires onto a sedan.