This composition is just three arpeggiated diatonic major chords : C (tonic I), F (subdominant IV) and G (dominant V) of the C major scale. Those three chords are probably the most widely used chords in the whole musical world! The lead voice is the predefined BASS7 patch, whose pitch is raised by a couple of octaves. A little bit of delay and you are done for the day.
For more information on diatonic chords, in particular the roman numeral numbering, you may want to check the harmony post.