Make a post on the 'Issues' tab of the SolarsSupremacy/sOS repository.
Make sure there is an issue posted about it and that you put in the description (or comment if there already is one) that you are fixing the bug yourself and will make a source pull request.
I strongly recommend you join our Discord server (avaliable in README.md). We would be happy to work with you or help you work with us on our tasks. However, if Discord isn't an option, making a pull request and including details of what you changed/added and why you did it would be the best optoin.
We don't have a universal place for uploading / downloading apps yet, but we have a channel in Discord for it. Again, I recommend you join as it's arguably the most important part of the sOS community.
Thank you!