I remember, from the 1990s, when I last used Dreamweaver (2.0?), it was a WYSIWYG interface. It would let you create drop down menus. Where do I look for this on Brackets?
Brackets is not Dreamweaver. You are expected to know how to work with code and/or frameworks like Bootstrap, Foundation, jQuery, etc....
This responsive drop-down menu changes from collapsed & vertically stacked on mobile devices to horizontal on desktops. See this link for an example and code tutorial..
Or if you use Bootstrap for your responsive layouts, try this code demo.
Just to clarify a bit, none of those 3rd party extensions will work in Brackets or the very legacy Dreamweaver 3 (not CS3).