Audio.h Library Issues
Occasionally people do not realize how many platforms the Arduino paradigm has been ported to.  In almost all cases the ported to platform far exceeds the features found on an Arduino Uno.  So there exists a considerable amount of software that can not run on an Arduino Uno or on an Arduino Uno with out additional hardware.  But, usually, such software is surrounded by "text", "web-pages" and other "readme"  type files explaining the situation.

For the Arduino Audio library, the web-page says this:


  Audio
  
  Compatible with Arduino Due only
  
  The Audio library enables an Arduino Due board to play back .wav files
  from a storage device like an SD card.
  
  The Due uses the DAC0 and DAC1 pins to play sounds.