Hi Peter,
I don't believe there currently are any tutorials, at least at NCAR, that are focused on stratospheric aerosol injection in CESM. There is of course a tutorial on general CESM use:
which includes a section on atmospheric chemistry and WACCM (which is the high-top version of CAM within CESM), which can be found here:
but again, none of the tutorial materials are focused on SAI specifically. Of course if anyone else on the forums knows of a tutorial then feel free to chime in here.
Anyways, I hope that helps, and have a great day!
Jesse