Make sure you have a permission role with set permissions; Create a role.
If you would like to invite a Vault Admin click here.
Step 1: Navigate to Invite Users next to the role you would like to invite the users for;
Step 2: Fill in the email address(es) and select Next;
Step 3: Determine the Q&A role per user and select Next;
Step 4: You can add a custom invitation text for additional information. select Send.
NB: When users are invited for a role in a Work Vault, an extra option appears.
You should select whether you are inviting internal or external users.
When External users is selected the Vault will be published to Project Vault automatically after sending the invitations.