The classic way is that people forward him the scams or he finds them in web searches. There is a relatively new technique though: scammers often have victims

The classic way is that people forward him the scams or he finds them in web searches. There is a relatively new technique though: scammers often have victims call them back once the victim has bought gift cards or whatever. So if once you get one of those callback numbers you can just call in pretending to be a victim in process. The scammers don't currently have pipeline management adequate to know if you're really a victim or not. This lets you skip a bunch of the early and failure prone stages (scammers hang up calls eagerly at the beginning if they get the slightest hint you're not a real victim) and go right to the end game where things are much more fun and the scammers are much less likely to bail out.