Click on the music file, then the box with arrow in the right top corner.  
Music Files will open in a different tab.  

The chants are generally ordered as one would likely use them -- i.e. grounding, casting, quarter calls, invocations, etc.   Most chants can be used for several purposes.

Apologies for the poor sound quality, but the chants are clear enough to learn from.  
We have not given the names of the authors, as we don't know many of them.