Hey Bill,
The indicated link is the automated way of putting all images in one calibration group.
The menu opens by clicking on +Images in 1D view (for people who don’t want to follow the link) 
Of course, this only works with one camera and a fixed lens.
Otherwise, the button above (Group) would be the correct one to use.
Thanks for bringing the attention to those buttons - I always do it on import or manually…