Users can be added as members to a project.
The users that have already been added on a Test Collab instance can be added to a project as its members. User roles should also be defined in order to add users as project members.
User roles define the access rights for various processes and entities available under a project in Test Collab.
More details on managing project members are available at - http://support.testcollab.com/index.php?pg=kb.page&id=24