Just head to the Admin section of the CMS and click on the New User button on the right:
Insert the full name and email address of the user you want to create/add and click on New User at the bottom of the page:
A welcome email will be sent to the recipient of the email account.
This is also the procedure to follow when creating a new network in your organization. In fact, a network is just a user with at least one podcast created.
Once the new onboarded user will create his/her new podcast, that will appear under that new network.