The easiest way to contribute to the Antimony project is by writing code in the language. The more the language is battle-tested, the more bugs can be found and therefore the language becomes more stable.
If you have a question, found a potential bug or want to engage with the community, you can join the matrix room of this project. If you prefer to stay away from matrix, you can also send a mail (or a patch) to the public mailing list.
If you want to contribute to the compiler itself, the easiest way to get started is to look at the open issues of the project. Usually, this is where important todo items are jotted down and bugs are reported.
You could also run the tests (cargo test) and see if any tests are ignored. Usually, if a bug is found in the wild, a failing but ignored test is written, so that it can be further investigated later.
As with all software, Antimony needs good documentation. Since Antimony is still in early development, things change constantly. This means that docs will be out of date in a lot of cases, or not written at all. Any help with the documentation is greatly appreciated!
If you want to contribute code, please open a pull request on GitHub. There is also a SourceHut mirror, if you're trying to avoid GitHub. Feel free to send a patch to the public mailing list. Check out this guide to learn about the patch based workflow.
Before submitting the code, please make sure that it is sufficiently documented and tested.