I may have not been clear -- the toolbar may already be there and you may just be overlooking it. In Word 2016, with Zotero add-on installed, there is a tab called "Add-ins". Are you not seeing that?
Good. This is getting somewhere. When I go to the startup folder and click on Zotero.dot, I get a Word screen with the Add-in tab showing, and the Zotero commands there.
I've tried that, found the folder with Zotero.dot, copied the pathway into Startup preferences in Word and still...nothing.
A
Anne