How do I make my printed document single-sided

This is quite easy, and is controlled by the media objects in Author-it that are attached to your topics - Chapters, Sections, Title Pages, Contents, Indexes, etc. These are any media object ending with the word "Section". Open each media object, go to the Print tab and make sure you change the Section Start setting to "Next page" instead of "Odd page". Also turn off the "Different Odd and Even" Header and Footer setting.

While you're in the Print tab, go to the Headers subtab and the Footers subtab - the "Even" field at the bottom of both should now be greyed out. You may also want to choose a different Header and/or Footer that is more suitable for a single sided document - experiment a bit. You can make your own Headers or Footers as well (but that's another story). Finally, republish your document.