Applescript: path to files in application's Resources
set myPath to POSIX path of (path to resource "audio.m4a")

    do shell script "afplay " &amp; quoted form of myPath


or

set myPath to POSIX path of (path to resource  "audio.m4a" in directory "Stuff")

do shell script "afplay " &amp; quoted form of myPath








You should look at the libraries in the library window of Script Editor.

In this case standardAdditions