As an admin, you can add new users yourself from the Settings tab of the CMS on the Organization section only if they were NOT previously registered on Spreaker, as explained here.
On the other hand, if you want to remove a user from your organization because a person decided to leave, you would not find an option in the CMS at the moment.
Don't worry, we are here to help!
For adding an existing Spreaker user to your organization or for removing one, you can contact us by clicking on the chat icon down on the bottom-right of this page. We can share detailed instructions that are customized to your organizations needs.