Organized in the context you quote means organized in time. Think of a musical piece or song as a graph. The Y axis is notes or sounds, and the X axis is minutes and seconds. When notes and sounds are planned to occur, in sequence, at specific points on this graph, relative to the X axis of minutes and seconds, then this is music.
Generally speaking, music is sounds organized in time.
By the way, with regard to the physics of sound, there is a distinction between musical notes and noise.
Musical notes are sounds that have, as a major component, prominent identifiable frequencies that repeat in a regular oscillating waveform. This is what we call a pitch or a tuned sound.
Noise refers to individual sounds that do not have a regular oscillating waveform, which is to say, among other things, that they have no recognizable pitch.
Now many percussion instruments do not produce a strong recognizable oscillating waveform, so technically a sound from such an instrument would be called noise. We call these instruments non-pitched percussion. But these are used in a musical context, meaning that the sounds they make are played by the player in a manner that is organized in time, so we regard them as musical instruments.