I’'m watching a video in the Academy and they talk about an outline function that is found in DATA/NEW and, in the video, is under located under GROUP. I find so such thing in my Pro 2.1.
Nor do I find it when I try to customize my tool bar. Have this been phased out since the video?
Yes, the video demonstrates DEVONthink version 1.x. There is no similar command in 2.x, although groups can be nested and hold documents, resulting in virtually the same result. And DEVONthink 2.x will create outline structures when it imports OPML files (say, exported from a mind map, Tinderbox, or OmniOutliner), as demonstrated in that video.
Much of the content in the DEVONacademy videos is outdated. See instead the Tips and Tutorials section of the Help > Support Assistant panel.