The files are on an external hard drive. I can drag and drop the files by album into the iTunes playlist. I can then open the album there and it shows the individual tracks in list view. I was advised by Apple if they show in playlist they should also show in the music folder, the one you mentioned in the upper left hand pane. They DO NOT show there. I tried to drag one of the titles from the playlist directly into the music folder and it still did not register. If I drag the same album from the external drive directly to the music folder, upper left hand pane, it does not show. I did a right click of the files on the external drive and under properties they do show as an MP3 file which I understand is the default for iTunes. These are the files that were originally converted from a wma format by using a program called Switch. They are all audio (Music).
Thanks for the response.