@SangeetaDhawan ...

The Studio interface does not let you control when to publish or not publish videos.  In fact, there are no options in the Studio interface to "publish" or "not publish" videos that you've added to your Studio library.  This is also true for Collections (I like to think of these as folders) in Studio.  The Studio library is your own.  Students cannot see the videos you've added to your own Studio library in their Studio view.  Every user has their own Studio library interface.  So, you'd need to embed any of your Studio videos into content pages within your course in order for your students to view said videos.

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