Hearthpwn

Rhok'delar is used to refill your hand with spells when you've used most of the spells in hand/deck. This deck sometimes runs out of steam quickly as it has limited draw power, so refilling the whole hand with more spells to cast is good for the deck.

Deathstalker Rexxar is used to control the board with the battlecry and create minions with the Hero Power.

Lesser Emerald Spellstone should be kept in hand when casting secrets, but not for all of them so you are not limited on casting secrets throughout the game. This should generally be kept in your starting hand to become more powerful as the game goes on, summoning more wolves.

And that's about it. It's a fairly cheap deck that's a lot of fun to play on ladder and is kind of high tier so have fun.