Create a new user.
New User
Under the Admin Menu, go to Manage Users.
Click on the New 
Button.
Enter in the following details:
- Given Name
- Surname
- Phone
- Job Title
If they are going to be a System Administrator, click the check box for that.
Click on the New 
Button to add the organization and role.
Select the desired Role and Organisation. Click Update once completed.
Then click Save.
This will send an activation email to the user for them to activate their account.