https://hackaday.com/ is a great community for learning hobby electronics.

For me it involves scrounging around for anything related as a jumping off point, and sniffing for important keywords and concepts to look up and branch out into learning. Usually it takes me a few days of exploration before I stumble upon a really good or authoritative resource of some sort, and I end up mapping out the internet locations of related communities and resources in the process.

Of course, it's much faster when having experienced friends or acquaintances to help you navigate.