I’ve just begun copying CD books into the MP3 format. I renamed the tracks from each disc 01-01.mp3, 01-02.mp3, etc. As they replay they scramble so I wind up listening to 06-01.mp3 then 05-04.mp3. I haven’t found how to title the discs and tracks so they’ll play sequentially.
The Clip sorts by ID3 tags, not filenames. You can use the free program mp3Tag to give all the files the same album tag, and to set the title tag equal to the filename(select all, filename-tag, save tag), or else you could have mp3tag sort the files in a folder by filename, choose select all, then autonumber, then save tag. Delete the files on your player, then copy them to the player again(to the audiobooks folder on the player).