Adding audio files (.wav or .mp3) that you or your students have created can be done in two ways...
1) Upload your audio file as an attachment to any page (maybe a File Cabinet style page would be handy here), then viewers of your site will "download" the audio file to their computer to be played.
2) Embed an audio player on your Google site page so viewers can "play" the audio clip without downloading. (See the example here- https://sites.google.com/a/aea267.k12.ia.us/test-3/https://sites.google.com/a/aea267.k12.ia.us/test-3/)
Upload/attach an audio file (.wav or .mp3) to your Google Site.
*Keep in mind that this method will require your viewer to "download" the audio file to their computer to be played.
Tip... Somewhere in the body of the page write a short narrative about the audio file, remind viewers to look at the bottom of the page, and how to download.
Embed an audio file (.wav or .mp3) to your Google Site.
Very Important... To embed an audio file to be "played" on your site, the audio file must first be uploaded to your Google site either as an attachment or upload to a File Cabinet or attachment page.
Note... There are a couple of audio gadgets to choose from. Try them both to see which one you like:
Try it with this .mp3 file-