How do you burn music on a DVD rw?

There is no industry-accepted format for a music-only DVD disc in the same way there is 'Red Book' CD Audio discs.

You could burn the music data files (WAV or MP3) onto the disc as data files, but only DVD players, DVD-equipped game consoles and computers would be able to read them. Any data burning apps, like Roxio or Nero, or freeware solutions like ImgBurn can create these discs. The fact that the disc is re-writable doesn't make any difference these days. All DVD drives can read rewritable discs.