Version 9/10 setting the root term via ID not available

I'm pretty familiar with this module on D7. I want to use it on a D9 site in the same manner but I don't see how to configure it such that the root of the tree is tied to a specific termid and displays only those terms under it. I seem to recall this being a global setting on the D7 version, but I don't see any global config options on this new version. Is that function still available and if so, where do I configure it now please?

Thanks for your time and thoughts.