There are at least two ways to do this, but the easiest way is this:
1. Insert a section break between pages 3 and 4 (Insert | Break | Next
Page).
2. With the insertion point in Section 2, View | Header and Footer. This
puts you in the header pane and displays the Header and Footer toolbar.
3. If you want the page number in the footer, click the Switch Between
Header and Footer button on the H&F toolbar.
4. Click the Same as Previous button to turn it off. This unlinks the
header/footer in Section 2 from the one in Section 1 (so that you can leave
the Section 1 header/footer empty.
5. Click the Insert Page Number button to insert a page number. Use
paragraph alignment or the built-in tab stops (which will need to be moved
if you've changed the margins) to position it left, right, or center.
