The original reply said one dabbled C++ via "creative coding, graphics programming, etc.", which definitely needs dependencies from the beginning. Can you draw a nicely shaded triangle only with the C++ standard library?
> If the library exports no cmake config and you have anything exotic you can put together your own cmake find modules, and proceed to follow step A.
They are not exotic, libraries without cmake config are common. So, as I've said before, people had to come up with their own find modules and this requires lots of trial and error to get it right. Guaranteed, it might have been possible to collect those into some sort of registry (a la DefinitelyTyped for TypeScript .d.ts files), and probably something like Conan can provide that, but ideally that should have been built into CMake. And keep in mind that Cargo---something we were comparing against back in time---does all of them declaratively. (Arguably, from users' perspective, it can handle C/C++ dependencies better than CMake!)