Google-integrated organizations that signed up for Jostle through the Google Marketplace have some extra functionality in Library.
If you haven't already initialized your Library, you will need to create a user for it in your Google domain first. See this article for more details.
Jostle uses a Google user and creates a Google Drive volume that is private to your organization. You can use an external Google Drive client to keep a local copy of your documents in sync with your Jostle Library. However if you do this you should modify files in Library rather than in Google Drive directly.
For more on Google-integrated Libraries, go here.