Once you have set up your project for Unity Services, you can enable the Collaborate service.
Select Collab in the toolbar and click “Start Now”.
With Collaborate now turned on, write your first message and publish your files. These files will be saved to the cloud and shared with your teammates (see below).
Is something described here not working as you expect it to? It might be a Known Issue. Please check with the Issue Tracker at issuetracker.unity3d.com.