Hi, I am new to the game and I have some questions about rules.

a) Can creatures attack in a turn they came to play?

b) How does th Ambush ability works? I have cards with this ability, but no rule text

Thanks for answers.

a) Yes, but note the first player skips the battlefield phase of her first turn.

b) Ambush X is a new keyword in the Eternal War cycle. The Ambush X keyword is active even when on a facedown development. After the Declare Attackeers step and before the Declare Defenders step, the defending player can pay the Ambush X value on a development in the defending zone to turn it faceup. That card has “ambushed.” The defending player may ambush any number of developments with Ambush X as long as he can pay the Ambush X value. A card that has ambushed is no longer considered to be a development but instead becomes its printed card type. If the ambushed card is a unit, it must be declared as a defender during the next Declare Defenders step. After all cards have ambushed, resolve any game text on those cards as separate actions.

Thank you very much.