Importing Files On Music Server - Totally Confused

So, I just started ripping my CD collection to an external hard drive in .flac using dbpoweramp. So far, so good. Ultimately, I plan on purchasing a music server with an internal hard drive (like the Sony Hap-Z1ES) in order to transfer the files from the external drive to the music server. Can I do this through a USB function on the music server itself or does it have to be via wireless or ethernet? My listening room is not wired up for ethernet, so it would have to be wireless. Just trying to get a handle on this newfangled and unnecessarily complicated methodology ... personally, I much prefer the physical media, but it seems that the era of my beloved CD is fast approaching its tragic end. Any advice on this as well as suggestions for a music server would be much appreciated. Thanks.