Outside a call - Tap Share screen. Connect your presentation source via cable or Proximity. You will now be able to share the selected content of your presentation source. Tap Start sharing. If you choose not to share content, press the Home button to return to Home screen. Tap Stop sharing to halt your presentation.
While in a call - Tap the Home button to produce the buttons on the display. Tap the blue Share screen button. To return to call now, tap the green field (Tap to return to call) along the top of the screen. Connect your presentation source via cable or Proximity and tap Start sharing. You will now share the selected content of your presentation source. Tap Stop sharing to halt your presentation.