I just recently struggled through and figured this out. Make sure your USB port is in MSC mode. Then make a file folder on your desk top, and put your book MP3 files in it. Use windows explorer to open your clip, media files, audiobooks folder. Drag and drop your book folder from desktop to there.
When you are disconnected from the computer, you access audiobooks in the clip from the music menu - its about the last category in there.
