Sane

Putting some information in a listbox won't automatically tell it that it should play the next song. It can't read your mind, unfortunately.

You have to set up an "event" to be triggered whenever a song reaches the end. Then link that event to a subroutine, which you will write, to simply change what song is playing.

I don't have the name of the corresponding event, but maybe this information can give you a push in the right direction.