In my mind...all music is just arrangement.I got it like this
Using samples of completed songs
Using samples of individual instrument noises
Live instrumentation
You can interpret it anyway u want breh
Some music is based on playing instruments, yes, but there are only so many sounds that a guitar can make. So its about how you arrange the sounds that the guitar makes. It's the same idea with traditional boom bap hip hop sampling. You take sounds from a few different records, maybe you modify them, maybe you don't. You put them together in a way that sounds good.
It's the same idea with these trap producers who I understood were using programs with preset sounds. They take the sounds and put them together in a way that sounds good (to them at least )