Two pieces of content on the support site which have been very helpful to new customers in the past are our CableCARD and HD Setup wizards. These flash-based presentations will walk you through the steps of setting up your HD TiVo box.
CableCARD wizard: http://tivo.com/cablecardhelp
HD setup wizard: http://tivo.com/setup
If you need additional help, please chat with us online at http://tivo.com/chat.
The TiVo Team