In your open document in OpenOffice.org:
- Open the Styles and Formatting window [F11] (or choose Format – > Styles and Formatting).
- Click on the Page Styles icon (fourth icon from left).
- Default should already be highlighted. …
- In the dialog that appears, give the new page style a descriptive name, e.g. Landscape.
Right click on Default and name the new Style landscape. Set the Next Style to whatever the next page should be--probably landscape is best. Click on the Page Tab — change from Portrait to Landscape.