FPSC doesn't support MP3...
you will need to convert your sounds to WAV or OGG
one cool and simple tool for this is Audacity
But you won't need to know much about sound zones... once you pass throw it, the default script starts (per default soundinzone.fpi) and the sound in sound=$0 (means the box where you browse for your sound in the editor) is played.
You can also open the FPI file and enter the sound location there (it
must be stored in the audiobank folder and you must write sound=audiobank\YOURSOUNDLOCATIONHERE).
Hope that helped
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