I use open source self hosted software everyday. I love the community and I would love to be able to contribute to some of these projects.
As far as code goes, I basically no nothing about how it works. I see the development section of the repos I use and again, I’ve go no idea how it works.
How can I teach myself how to offer small improvements to the projects I use?
Don’t learn C++ before C. C++ is a massively more complex language whereas C, once you understand the fundamentals, is quite simple.
If you want to work with projects that use C++, then by all means.