One other method (also not that intuitive) is to right-click on any tab and uncheck the "Minimize the Ribbon" option.
At least on my computer, it is
Ctrl+F1.
F1 brings up Help, such as it is.
BTW, it is called the Ribbon in Word jargon, not the menu bar. Searches for "menu bar" and Word are likely to lead you to the older versions which do not have this feature or its related problems.
The Ribbons of Microsoft Word 2007-2013