For submitting the project, create a new fork of the hackathon repo, and add your project folder inside hackathonRepo/submissions/ and add a markdown file that provides project description, issues, team members and any additional materials used in the folder.
You can refer submissions/exampleProject folder for reference.
Be sure that your project's folder links to the repo you've been working in, and contains any other supporting materials that you want evaluated by judges (such as links to a pitch deck or demo video).
Once ready, submit via a new pull request.
Opening a Pull Request establishes your project as an "official" submission
You can open a PR before the submission deadline and continue to work, but all materials must be finalized before the end of the hackathon. Any commits to your project submission after the deadline will not be considered.