How do I create a horizontal master page?
According to the Adobe documentation that I've found, the way to do this is in Document Setup. But I don't want the entire document to be horizontally aligned. I just want one page to be horizontally aligned. I thought the way to accomplish this would be to create a master page with a horizontal alignment. What is the easiest and best way to do that?
Which version of InDesign?
Are you preparing a file for print or presentation?
If it is print, I would keep the orientation of all pages the same, and rotate content for the horizontal page. Rotate the Spread View as necessary to edit content.
If it is for presentation, it depends what version of Indesign you are using.
-If it is CS5 or higher, then you can define multiple page sizes in one document
-If it is CS4 or lower and final product is a PDF, then I would keep the orientation of all pages the same, and rotate the horizonal page in Acrobat