"Show on catalog" controls whether or not the course will display in the course catalog.
To set the catalog display options:
Navigate to the course
Click "Course settings."
Check the checkbox for "Show on catalog" to display the course on the catalog. Uncheck the checkbox to remove the course from the catalog.
When reviewing a course as a test learner, uncheck "Show on catalog" and publish the course. Review the course as a learner, and then check "Show on catalog" when the course is ready to be viewable for other learners.