Press the Source button on the projector or one of the Source buttons on the remote control to select the correct input source. Allow a few seconds for the projector to sync up after pressing the button.
Press the Blank button on the remote control to make sure the picture hasn’t been turned off temporarily.
Check that the Power light is green, not flashing, and the lens cover is off.
The projector may be in standby (or sleep) mode. If the Power light is orange, press the Power button to turn the projector back on.