I'm trying to create a playlist of some simple .mid files located on my computer hard drive.  There seem to be all kinds of instructions on how to do  complicated things, but I can't find how to do what should be this simple operation.  Here's what I've done:

 

From the file menu, I chose add to media library - by searching computer.  I chose my sub-folder, clicked search.  It says 58 files were added, 100% complete.  But where did they go?  I can't find them listed anywhere in media library or playlist.  I'm probably just not looking in the right place, but I'm baffled. I know .mid files can be played on WMP, because if I click an individual file within my folder list, WMP pops up and plays it.