How to select PSU?

I am confused. I want the potential to power 16 HDDs and am looking into 750w PSU to do so. But i cant figure out how to connect and feed it from the PSU. I seen molex to sata connectors but its recommended to only have 2 SATA on this connector. the 750w PSUs dont really come with many PATA and sata anyways now, so how do people do it?