You definitely need a way to control it and an ipad works best for me, but so will iphone, android, or any computer. You'll need the app mentioned above.
You'll need a USB dac.
And a wifi router that the stream player can connect to via Ethernet. The streamer will become a part of your home network. I use an old Apple airport.
To get music files into the hard drive of the stream player. I used my MacBook Pro to rip all my CDs into Wav files using XLD app. I have it configured so that when I insert a cd it automatically rips it into the Stream player. Since the stream is connected to my network, it shows up as an external drive would, or like using a memory stick would.