Let me save you some time, Nanji. No, what you're trying to do is not supported in Word 2016 for Mac. If the VBA buttons and menus on your 2011 .dotm template are important to you, you should just continue using 2011 and check back in for news about Word 2016 in a year or so.
In my experience, about 50-75% of the stuff I built into my Word 2011 template is inoperable in Word 2016.
Word 2016 doesn't support floating toolbars or ribbon customization, and it doesn't have a fully functioning VBA editor, so it's not even possible to re-create your 2011 .dotm template from scratch within 2016.
Adding custom dropdown menus and most of the other UI customizations you are used to from Word 2011 are virtually impossible in Word 2016.
But wait, it gets better: 20-30% of the VBA code for those macro buttons you want to appear in the drop down menu will probably also be broken or buggy in Word 2016.
You may find advice elsewhere on the internet suggesting that you can build a new .dotm file on a WINDOWS machine with a current copy of Word for Windows, then load .dotm that in your MAC version of Word, cross your fingers, and use trial and error to see what, if anything, actually still works on your Mac version of Word 2016, but you will just end up tearing your hair out trying to do this. Trust me, I've been there.
You might make a tiny bit of progress doing things that way (build/code in WinWord then test in MacWord)--I managed to put some macro buttons on a custom ribbon tab using instructions I found on Microsoft's Mac Word Insider forum--but it will take forever to do something that took 5 minutes in Word 2011, and at some point you may reach a dead end without actually being able to finish what you're trying to re-create in Word 2016.
You may also find promises that Microsoft is "working on it" and that they definitely have plans to add these UI features back into Word 2016 for Mac, but that day may never come.
I've been checking the new releases religiously since January 2016--a full year now, woohoo!--and at one point they said that all the missing features would be added back by summer 2016, but so far all they've added is the ability to put a few buttons on the Quick Access Toolbar. Those QAT buttons, by the way, are limited to built-in Word functions, not custom dropdown menus like you want to do, or even customized buttons for individual VBA macros.