First, save the sound file in the same folder as the JMatch.
Then, in JMatch, select Insert -> Media Object, type the name of the sound file in the "Media file" box, click the "Add Windows Media Player" button, uncheck the "Add a sample link" box, click "OK" then save the new JMatch file.
Next, upload the new JMatch file and sound file to Moodle. When you add a the JMatch to Moodle as a HotPot activity, be sure to set "Force media plugins" to "Yes"
That should do it
all the best
Gordon