For example, all my music is ripped from cd's. So when I move it from comptuer to computer I simply move the files (copy, drag and drop, etc) and then import them into iTunes. Once they're in there you can sync them onto your iPod.
iTunes Match needs to be set up from a working iTunes library on a computer. If the original poster has lost their library and now only has their media on an iPod, iTunes Match won't rescue it for them.