You can find the Public courses you created by logging in on the website, then clicking on your profile icon in the top right corner and selecting 'My Profile': you will find your Public courses in the Courses > Teaching section.
Please note that this section won't show your Unlisted or Incomplete courses - you can find these in your Dashboard. Simply click on Home, and filter by 'Teaching' in the top right corner. This will show you all the courses you created or that you are contributing to.
To change the status of a course from Unlisted/Incomplete to Public, please click on 'Edit course' in your course's main page, click on Details and then select Public from the drop-down Status menu.