Sharing and collaborating with Zotero/Juris-M is easy to do but must be set-up in the web version of the app at http://www.zotero.org. Log in and navigate to the "Groups" tab across the top of the page. Create a new group for your research project, team, or any collaboration. Choose the level of privacy most appropriate for your work.
Under "Member Settings", send invitations to join your group via email.
All group members will now see the Group Library in both the desktop and web apps. Members will be able to add sources and start new collections according to the permission assigned in the group settings.