at the top on the
format toolbar
on
the Header/Footer toolbar
Word displays the "Footer" Window.
Click the Center button at the top on the
format toolbar
This will center the text in the footer.
Type Page
Press the spacebar once
Click the "Insert Page Number" button 
Word will insert the current page number in the footer.
This completes the footer.
Click the Close button 
on the floating toolbar
Word will not display your newly created header or footer in the current document view. We will change the view on the next screen.
Now you try!