Please refer to page 14 of your user manual for instructions.Before playing 3D videos, please turn off Horizontal Keystone Correction and Screen Zoom inside Settings.Open the "Movie Player" app, then open the video that you wish to play in 3D. Select the 3D option in the menu bar and select the appropriate 3D mode.Note: 3D glasses are not included with the projector, but you can use any active shutter 3D glasses for the projector.