NOTE TO EDITOR:
The media library uses your SiteBuilder Media space which is typically much greater then your regular site space. It is the best way to make audio and video available on the site. You file formats should be MP3 for audio and MP4 for video properly compressed for the web. This will allow you media to be viewed on mobile devices as well as PCs and tablets.
The Media Library allows you to enter descriptions and add categories so users can sort by say sermon series. It also can automatically creat a Podcast. For a complete description of how to use the media library go here: http://churchsquare.com/main/site_tips___how_to___/edit?sctop=0#5