Ideally the game should install from the DVD, but in my experience it will not do this without an internet connection.
I've not had good luck with Steam customer service. I bought access to Bloodlines from them and the game would not run after installed, and Steam customer service replied (and they were serious

), that I should pull half of my RAM out if I wanted to play the game. The game works now (with my RAM intact), but no thanks to them.