How do I Set Up Duplex on an HP LaserJet 4050N?

1. Turn the printer off using the power switch on the front-right corner.
2. Remove the plastic dust cover located above the paper tray on the rear of the printer. Grasp the duplexer accessory with both hands and push it straight into the slot above the paper tray.
3. Turn on the printer. Open your computer's Start Menu and choose 'Control Panel.' Click 'Printers and Faxes.'
4. Right-click 'HP LaserJet 4050N' and select 'Properties.'
5. Click the 'Configure' tab. Tick the box marked 'Duplex Unit' by clicking on it. Click 'Ok' and close the window.