I have only one DVD disc. How do I watch it on both the screens?

To view the DVD disc on both the units, play the disc in B-Unit and connect the AV-OUT socket of B-unit with the AV-IN socket of A-Unit using the provided AV cable. Now press the IN/OUT button of the A-Unit to set it to the “IN” mode so it may receive the AV content coming from B-Unit via AV Cable.