This is a very crude Java melody editor. It can only handle single-part notes, which sort of reflects the inability of Java to play more than one sound at a time. Java doesn't allow that sort of low-level sound manipulation.
All sounds have to be prepared in advance and downloaded over the net.
Each note you can use corresponds to an individual audio file and the applet needs 29 of them. The controls are relatively easy. You only work with the notes . The applet takes care of putting in the appropriate pause symbols and keeping track of where the melody ends. To place a new note somewhere, make sure there is logical room for it in the bar.