For Section Breaks go the Insert option on the top of screen. Select Break from the drop down menu. Then select Section Break (Next Page)
For section breaks, place cursor at the end of the text before you need the section break and click Next page. Section breaks are used at the end of chapters or other parts of the document that require individual formatting.
Section breaks also allow putting different text and different types of page numbering in the headers and footers for different sections.
You have disconnected the headers and footers in the sections prior to and following the current section of pages. This will prevent any changes you make to the page numbers on the landscape pages from affecting the numbering on other pages.