To report an issue with the website please open a new issue.
After cloning the repo and installing the dependencies, you can run a local instance with the npm start script: any changes you make to the source code will be shown in your local instance.
If you want to test out the resulting build, you can use npm run build.
Make sure to commit your changes to a branch and test them by running npm test. Additional tests will also be run by GitHub Actions when you push to the repo or open a PR.
After you've tested your code open a new PR and wait for a repo maintainer to review it.