I don't think anyone knows how the packaging is going to work.
I get the impression that it will be faction packs, like bloodbowl. Except they will include relevant cards. And you use those included to build your deck. But that's just an impression.
I did notice they.number the cards. One said "31/347" which leads me to believe that either the core comes with that many cards, or that many cards are in the entire game. Which one is true is anyone's guess.