Uploading Your Audio and Video
You can upload audio and video files such as MP3, MP4, FLV same as attaching files by clicking the 
beside “Add media”.
After upload the audio/video file successfully, click “Insert into post” button.
You shall be able to play the MP3 at your site upon successfully uploading the MP3.
Note : You must, however, have the appropriate plug-in components installed for your PC and browsers, e.g. Flash, Quicktime or Media Player.