See also:

Supported Media (Disc Types)
The MP3 file recording media supported by the radio are CDDA, CD-R, CD-RW, MP3, and CDDA+MP3. ...

Playback of MP3 Files
When a medium containing MP3 data is loaded, the radio checks all files on the medium. If the medium contains a lot of folders or files, the radio will take more time to start playing the MP3 file ...

Buttons 1 - 6
These buttons tune the radio to the channels that you commit to pushbutton memory (12 Satellite stations). ...