Two-Sided Printing

The available options for two sided printing vary from printer to printer. In every case it involves clicking on the "Printer..." button in the lower left of InDesign's Print dialog window and accessing the features for that printer in regard to two-sided (duplex) printing. It may be under a Printer's Feature Menu (possibly there will be a Layout 1 option within that and Duplex options within that). It could also just be as simple as clicking on two-sided printing within the Printer's specific dialog window. It is very different for all printers. Your best bet is to consult the documentation for your specific printer or do a search on the Printer's website.