Hearthstone: Heroes of Warcraft brings strategy card-gaming to life with cool animations, smooth graphics, and tight gameplay.
Pick a class
Each of the nine classes has different decks that give you different abilities. You'll notice that many classes don't yet have the 20 earnable cards -- you can play real players or practice games to fill out those decks.
Once you start the game, you have the option to replace cards in your opening hand. The level (and crystal requirement) for the cards are in the upper left of each card. You might replace high cards here so you can play more in the early game, but some of those high cards might be really important later.