Scheme Managers can add new users. Please go to the top right of the page:
Then the Scheme Manager will first view his own profile including options to change e. g. password and mail address. On the right side, there is a small green icon 'Invite new user' which you can also spot on the screenshot below.
You can then enter all details like names and roles and set the language to English or Spanish.
If you click on 'Send Invitation' the new user will get an invitation link to finish his registration