One of you is 'Admin'
You, the initiating parent, are annointed the Arithmetika Administrator of your family group account. The account administrator manages the details of the student children in your family (logging in, etc.). Administrators are also the prime contact person between the family and Arithmetika on the Web.
An Arithmetika account is fully self-managed
As Admin you very quickly add details of all the students. You don't even need to add each student's details. Just tell the students the Access Code for their family group and the link (URL) to sign up. You can also delegate or share some of the responsibility for user management with teaching colleagues by making them 'Deputy Admin'.
Not a parent or guardian?
From the top menu above, select Tutors, Teachers or Students