Descriptors also were kind of a mystery for me until I realized that they're just a binary structure with a fixed format that the host reads and interprets.

The device descriptor is easy enough to get right as it doesn't have too many fields and every USB class just defines in the specification which Class and SubClass it uses for its interface descriptor as well as which endpoints that interface needs to have. And that's, for the most part, all you need for the host to recognize your device