How do I add district administrators? I want them to assist and help our schools.

You can invite an administrator by navigating to your Profile Page and clicking the Green "Invite Admin" button on the right of the page. 

From here, enter the email address of the person you would like to join as an Admin. Producer will then send them an invitation to that email address to provide access.

Please note that only the "Producer" Account (the original for your institution) is able to invite new users. Any new users invited as an "Institution Admin" will be able to access all functions on Producer including uploading media, moderating content, etc. aside from sending invitations for new users.