All sounds files are mp3 files. If you've configured your browser to play mp3 files directly then clicking on a button above should open a new window with a sound controller in it. If the window is blank then hopefully you've been prompted to download the sound file. If nothing has happened then download and install the latest Apple Quicktime (or the format player of your choice) and configure your browser to play mp3 files directly, or to open mp3 files with the Quicktime plugin.