Click into the first paragraph of your first page.
Then select > Format > Paragraph > Text Flow.
Under "Breaks", check "Enable".
Make sure it says "Page" as Type, and "Before" as Position.
Check "With Page Style" und choose "Default" as Page Style or any other according to your needs.
Now choose the page number you need. Note that the "0" in the Page Number dropdown list doesn't denote a page number but simply means that the present page number won't be changed.