Hi @ROBERTAENGEL,
You can't directly enroll into a course form Canvas commons, rather you'll need to have an existing course shell in Canvas to import the commons content into. The How do I import and view a Commons resource in Can... - Instructure Community (canvaslms.com) guide should show the steps to take to import the content form commons into one of your courses. If you don't have the ability to create a course shell for this purpose, you can work with your local Canvas team (usually in the eLearning / IT / Digital Education areas) to get that step done for you.
Hope this helps!
-Chris
