As a Campaign Owner or Collaborator, you will have access to manage access to the Campaign by clicking the Gear icon to the right of the Campaign row on the user dashboard, or the gear in the expanded Campaign menu on the Data Rail on the left side of the screen.
The User Access menus in the Campaign Management section include Account Users, Campaign Access and Invites.
The Account Users section lists all available account users that do not currently have access to the selected campaign. Assigning a role and clicking the + icon will allow you to easily give those users access to the campaign. Owners can assign all roles to users they invite, however Collaborators will only be able to add new Collaborators or Viewers to the campaign.
The Campaign Access section details all current users with access to the campaign. Each role currently assigned to the user is displayed next to their username, and can be changed by clicking the dropdown menu. If a user should have their access removed, clicking the 'X' button will revoke their campaign access, and they will be returned to the 'Account Users' list.
The Invites section will display any pending invitations for new users, as well as the role that will be assigned to the user when they create their user account. New users can be invited by clicking the + icon at the bottom of the Invites section, and entering a user email address and role for the new user. Invites expire 7 days after they are created, if not claimed.
Account Administrators can invite new users to the account from the Users tab of the Account Settings panel.
Clicking the 'Plus' icon below the list of user names will allow the Admin to add a new user to the account, and select which campaigns the user should have access to.