First, all participants need to have an RDMO account. Then one of the team members (the so-called owner) has to set up the project. Now additional group members can be added by the owner of the project. The owner needs either the email address or the username of the group members.
The owner can assign a status to each group member. Guests can only read the DMP by not edit it or change the stetting. Authors can write new text and edit answers. Users with manager status have almost the same rights as the owner. They can create snapshots, modify project information etc., but they cannot delete the project.