Once your onboarding exam is reviewed, you will receive an email alerting you of your onboarding status. You can also look at your course's main page to see your onboarding status in that course. Please note that if you were approved for onboarding in another course within the last 2 years, you are approved for onboarding in all courses on edX.
If you did not pass your onboarding attempt, you can reset your onboarding attempt yourself by going back to the Onboarding section of the course and clicking on 'restart my exam'. This will allow you to be immediately reset and try again. Please make sure to restart your computer before re-attempting onboarding. You will usually receive your new onboarding results within 2 days.