Ipad "Edit In Kami" not found

I am new to Kami… It works GREAT on my Chromebooks.
I am trying to set it up on my Ipads and am having touble…
This is going to be for my K-3rd Graders simply to “write” on PDF pages sent by teachers. (Hopefully they’ll do more).

As a student, should they access from Classroom or Chrome Browser?
Should I see “Edit with Kami” as in the CBs?

Is there any solid documentation I am missing describing a FULL HOW TO - from setup to assign - to edit - to turn in?