Are there instructions as to adding extensions within xxxToolbars?

I’ve experienced frustrations having to switch back to menu commands to locate an extension within menu pulldowns

Access to extensions macros depends on the extension developer.
Some extensions have their own menu or toolbar
Other extensions add entries to LibreOffice menus.
and finally other extensions use the menu Tools > Addons.

If you tell us the name of the extension we may indicate what type of input uses.

With xxxToolbar you mean the Notebookbar aka Tabbed UI? If so this might be of help: Development/NotebookBar/Extensions - The Document Foundation Wiki