To dub a DVD, first press Setup on the remote. Then select Recording (use the Up/Down arrows and then press OK). Navigate to and select Dubbing Mode. Select the direction for the duplication. Then press Setup to leave the Setup menu. Then press DVD to ensure that the unit is ready to play the DVD. (Press VCR if you are dubbing a video tape.) Then Press Play to advance to the section that you wish to duplicate, if needed, and then press Pause. (Press Pause a bit early; the dubbing process will lose about 5 seconds.) Now, press the other Mode button (VCR if recording to tape, DVD if recording to DVD). Next press D.Dubbing on the recorder or the remote. (The button is to the right of the Channel Up/Down buttons on the recorder. It's near the bottom left on the remote.) Press Stop when the section to be duplicated has been played in its entirety.
The Magnavox ZV450MW8 was manufactured by Funai with the Magnavox name. Thus Funai Service has the manual available: http://www.funaiservice.com/manual2012_search2.php
. The direct link is http://www.funaiservice.com/manuals/MAGNAVOX/ZV450MW8/ZV450MW8.pdf
. The directions for dubbing a DVD to VCR or vice versa start on page 48. Note: copy protected items cannot be duplicated.
I hope this helps.