Cool, where could I find some decklists? and this game has diferences on the ruleset compared to the paper?
If you are just starting, they give you a small collection of cards, but to get more, you have to unlock cards (very slowly, or pay $$$). Someone on the internet has probably built some OK decks out of the starter cards they give you. I think red / white beatdown is best with the starter cards maybe?
Ruleset is intended to be the same as paper, but there are probably corner cases where stuff doesn't line up right. It's missing a lot of the cards from paper; they only release about half of the cards for each set in Duels. Deck construction is very different than paper - you are limited to 4 x of any common, 3 x of any uncommon, 2 x of any rare, and 1 x of any mythic.