Here we are with the finished timeline editing.

Save file As...whatever.

Now hit the F12 button (Publish Preview Default HTML) and you will see / hear the finished file. For longer audio files, this may take some time. This process does a couple of things.

It creates a SWF file with embedded MP3 audio in the same folder as the saved file. It creates an HTML file to display the SWF file again in the same folder.