How does Matt do those screeching/squealing noises and pick scrapes?

[PinkFloydMuserQ17]

Hi everyone. I’m a pretty new guitarist and I’m curious on how Matt creates the squealing sounds on the guitar when playing live, and the pick scrapes in Hyper Music.

I have tried looking at YouTube lesson on these topics, but the pick scraping doesn’t seem to work, and I head that for the squealing you strike behind the nut- but that doesn’t seem to work either (all I get is this creepy piano-like chime 😂)

Thank you ❤️