> Like what does "money laundering" look like on the ground, how would I know if someone around me was trying to do that?
You won't. Money laundering is giving plausible reasons for the government to think illicitly gained money is actually legitimately gained.
It usually takes the form of a business. Generally speaking the more service oriented the better (You wouldn't want to explain how a restaurant can serve 1000 people with 1 grocery store run. But a laptop repair business? Pretty easy to fake a few "I uninstalled a virus from mister smith's computer".)
> I've had some random Amazon items show up addressed to me, but I didn't order them, and I think that was part of a scam, but I never fully got my head around how it works.
That one is a fun one. You generally aren't the one being scammed, someone else is. It's (probably) triangulation fraud. [1] [2] Though it could also just be a scammer checking to see if a stolen credit card will buy things.
> I hear about various "work from home" jobs actually being scams, but what's going on there?
Generally, these are MLMs. It's usually targeted at stay at home moms. It's usually "be your own boss". And usually the business model is you try to recruit people to sell the products you are ostensibly supposed to be selling. Basically a pyramid scheme but legal because there's a product in the mix (really dumb that it's legal).
[1] https://www.npr.org/transcripts/1119606931
[2] https://chargebacks911.com/triangulation-fraud/