Firebase behaves differently here, students cannot be given a link, and two tabs can end up sharing one identity — which looks like work and notes leaking between students. Open the site instead:
https://chalklineschool.com/
Typing mathematics made user friendly v27
The teacher view is for you, not the class. Sign in once and this browser will remember you.
Everyone using the same class code shares a board set. Open the teacher view in one window and a student in another to try it.
No student has joined yet. Open this file in another window, enter the same class code and join as a student.