I have turned on Total Words in the Outline. However when I select the Manuscript folder in the Binder, I see the word totals of each SubFolder but not the total for the Manuscript itself. How can I see the total number of words in the manuscript?
The Outliner and Corkboard look “downward” from what you have selected, they does not show the selected item within it (you can imagine that the frame around the items is “Manuscript”, with the header bar and such—just like with the Corkboard you can imagine the background is “Manuscript”).
Fortunately however, seeing as how getting a total word count of your work in progress is a rather fundamental concept, we wouldn’t leave you without different ways of getting that number. 
Refer to §20.1, Goals and Statistics Tracking Tools, pg. 484 in the user manual.