For others following this, I figured out that in order to "add the new command", you should see a group in the tree called "Miscellaneous" on the left window. The new Menu item you created will be inside that group. In the attached image, I copied my new "Isolate" Command to my new "AMF" Menu.
EDIT: And then if you want, you can go into Plugin Manager > Edit Definition > ...New, and create your own name for that new group in the Workspace Editor, instead of it using "Miscellaneous"...
And you'll end up with something like this in the Workspace Editor... (Notice "Miscellaneous" is no longer there)
***BTW, sorry if I'm continuing this in the maybe the wrong thread? Please feel free to move it or ask me to, etc.