Making music means, interpreting a composition in a creative way. This is true for traditional musicans as well as for electronic artists.
Nowadays it is easy to create music. There are millions of digital sheet music (= midi files) available for essencialy every song ever has been written. With this midi files a synthesizer can produce an endless number of different interpretations of a song, with different instruments and numerous sound effects. Hard or soft, shrill or harmonious, classic or capricious.
A midi file is a collection of sheet music for a whole orchestra with up to 16 voices (= instruments or sounds). The notes for each voice are hold in a track and you can assign an arbitrary sound to each track to give it its specific character. So you can arrange the song in a creative way and create and publish your own interpretations.