If you bought the book on CD, the files are in .cda-format, and will not play on your phone, unless you convert them to .mp3 as described below.
On your Computer
- Copy from CD and Convert to .mp3 (Get a Ripping tool and set up ripping to .mp3 (Windows 10) )
- If each chapter consists of many files/CD-tracks: Consider making only one file for each Chapter, using for example AudaCity (this takes some time, like 1-2 hours if you haven’t used AudaCity before. )
- Consider changing the file names, so you see both the Chapter number and a Short title
- Copy the .mp3 files to your phone