Quick Summary
To add a new user:
On the page that displays the users under your organization, click the blue + button at the top right.
Enter all necessary and required fields and make sure to add the user to the correct organization. If it's a new organization, create the organization first and then create the user.
Once the user's account is created, an email will be sent to the user letting them know their account has been created and a password will be generated and included in the email.