The trades don't usually pay what people talk about on the internet. You can look it up. The better paying ones have years of schooling and apprenticeships. Many of the programs are harder than many college degrees. I have met some guys making really good money in the trades but it's not the norm and it's not a shortcut to money around learning.
Remember Joe the Plumber? Whatever happened to that guy? Why don't you look him up.
Is there a class on hanging drywall?
Yes they teach it in trade schools and maybe part of some construction degrees. I learned how to hand drywall from my dad and I'm pretty sure he learned from watching Bob Vila.