Make a pull request (hereafter PR). In the PR body, feel free to add an area label if appropriate by saying /area <AREA>. The list of labels is here. Also feel free to suggest a reviewer with /assign @theirname.
Once your reviewer is happy, they will say /lgtm. If you do not have write access to this repo, they will merge for you. Otherwise, click the big green merge button when ready to merge. If neither you nor your reviewer has write access, please /assign someone from kubernetes/test-infra-maintainers and ask them to merge for you.