The base is original from the producer (chords and melodies), but is complemented with elements that complement the song that come from samplepacks, usually, vocal chops, guitars, wobbles sections, glitch effects. It is the standard in which most of producers work, in a project you will find MIDI files made by the producer, but also melodic loops.
I sampled the Pad and gave it a new look, then I added a Vocal Chop and tweaked it so it could sound in harmony with the pad.
After, I made the super fire drums.
Sample pack BUYLOOPS.com - Free Loops Vol. 70
Loop name Another Year 135 Amin (Prod. evyskrr)