Hi and welcome to the beoworld!
Make sure you have put the music in a folder on the sdcard. The BS4 needs the songs organized like this:
folder1 (song1; song2; song3...)
folder2 (song1; song2; song3...)
...
this is the only way that the BS4 will be able to read the songs. IMO, the easiest way to put music onto an sdcard is to do it with drag and drop.
Music washes away from the soul the dust of everyday life. - Berthold Auerbach