Take setting the second page as "horizontal page" as an example to illustrate:
① Place the cursor after the last word on the first page;
② File page settings, which are set under the "Margins" tab:
Direction: horizontal; (Preview) Apply to: After the insertion point
③ Place the cursor after the last word on the second page;
④ File page settings, which are set under the "Margins" tab:
Direction: vertical; (Preview) Apply to: After the insertion point