Asklemmy

The best beginner guide I've found is bcae1. It's just some dudes blog, but he made it up as a basic electronics lesson plan with a focus on car audio. It'll help you to get a really good idea of how everything works together. I still regularly use the site as reference.

On YouTube, there's a channel called Car Audio Fabrication . He explains alot of stuff very well and will give suggestions on what equipment to buy. He puts a lot of focus on making a build look clean and professional.

For home stuff, parts express is the defacto DIY audio store. They have a lot of resources on their site from blog posts, how to guides, and even customer projects.

Crutchfield is easily one of the best sources for both home and car. Excellent customer support, virtually unbeatable. Lots of resources like parts express (maybe more). They do tend to carry more mainstream products. Which is fine. It's all quality products, but I do find that you're often paying more for Crutchfield. Both because a lot of their products carry name weight and are more expensive because of that, and because their customer support is good enough to warrant a little extra.

For car stuff, since I do competition grade builds, I like sounds solutions audio and Down 4 Sound. D4S' owner is very active on YouTube and Instagram.

Well, that's a lot of good places to start. Electricity is magic. Don't fool yourself into thinking it's not. Even after you "understand" it, it's still magic. The last link up give you is for Sparkfun. They're a retailer like parts express and Crutchfield with excellent guides/resources and community showcases. They're focus is on low voltage electronics like arduino and raspberry pi.

Anyway, have fun learning. If you have questions, feel free to DM me. I love talking about this stuff.