What has to happen for the Dallas Cowboys to make it to the superbowl?

I mean, i'm not a dumb blonde, beleive me I know how football is played. I just dont get the terms used. Like, clinched playoff spot and clinched home field? I mean right now according to Yahoo! NFL Standings the cowboys have Clinched Home Field... and that means?? Do they play another game? Do they have another chance? Are they completely out? I don't know because there isnt an NFC East Champ yet. Please help. Please, only serious answers. No, "It's gonna take a miracle" /:-}