Hi Paul,

Co-teachers are currently only available for classrooms in the MAP Accelerator and Khan Academy Districts programs.

If your class is not part of those programs, then I encourage you to take a look at the workarounds suggested here: https://support.khanacademy.org/hc/en-us/articles/203610350-Can-a-user-have-multiple-coaches-Is-there-a-way-to-add-a-co-teacher-

I hope this helps! Please let me know if there's anything else I can do for you!