Basic HDTV Setup but Hard for Newbie

ibmuser

I have a Viewsonic n2752w, a Motorola DCT5208 and a HDMI DVD player. I am not sure I have setup the cables correctly.... Comments are welcome. I have the Samsung HD85OB DVD player setup using the only HDMI port on the TV. The DCT6208 in connected to the TV using the High DEF Video and Audio Cables.
The rogers cable coming into the house is split with one end going to the the "TV in" port of the Dct5208. The other is into the "TV" port of the TV. This way I can record HDTV while watching regular cable.
This setup doesn't look right to me. The "DTV" port on my HDTV is not in use but the manual indicates there are a lot of features here but I have connected the regular TV cable to test but I get no Picture, and there is a "Scan for Channels" and many other features I never see.
So - 1 - What is the DTV port for and how come I get no signal?
2 - Splitting any cable is not good, but how can I get around it ?
3 - What setting should I use for Audio once I get into the Menu on the DCT6208

ibmuser

The DCT6208 in a single tuner box. There are no immediate plans for a dual tuner box in Newfoundland. DVI is for "Over Air" TV transmissions. Consider this item CLOSED.