If an entire group of players are new to the setting, I often suggest their character are all survivors of Cyre -- perhaps they served together during the Last War, or they could've been thrown together by the Mourning. This approach not only makes it simple for players to know little about their homeland (after all, they won't be casually strolling its streets or navigating its politics), but being from Cyre gives the party a shared loss and an easy explanation for why they're adventurers. They have no home to return to, and all they have is each other -- now do they want to help other Cyrans, or are they just looking out for themselves?