What is Canvas Commons?
Canvas Commons is a repository of course content made available from other instructors and institutions. You can browse through Commons to find sample courses to review. In order to view the content, other than initial views of pages, modules, etc. you need to import the content into a course shell. Course content can be shared with the public, only within the institution, or just with the instructor posting it.
Using the Commons to clone course content
Canvas Commons is very helpful when instructors want to share their content with others. If you just want to copy one course's content to another of your courses, you can do that easily with the Import Content feature, and do not need Canvas Commons. See the Import Canvas Course into Another Course Shell help document.