Starting with the 2005 remake and realized that its connected to the old series, how much do I actually need to know?

Started with the 2005 remake and I'm loving it so far, can't wait to get to david tennet since I saw the clips of him, he's what sold me on watching the show, but after the episode "dalek" I realized it's connected, so how much do I need to know? Does the original series cover anything important about the time war etc etc, or will everything be explained eventually?