There is no completely correct or incorrect way to contribute to open source. As long as your motivations are in the interest of improving the project, or contributing good resources to the community, I recommend going for it! Contributions come in all shapes and sizes. Even if you’re fixing a small typo in documentation, or refactoring a large section of code, your contribution is valuable and helpful. Keep that in mind.
Habitat’s core-plans is the central repository for packages/plans maintained by a group of volunteers. These plans form the basis of pretty much everything built with Habitat. From low level libraries and tools such as GCC, glibc, openssl to high level applications like Jenkins, Artifactory, and a whole range of others. The full list can be seen in the Github repository. Theres a bunch of things that happens behind the scenes of your pull request on the Habitat core-plans repository.