I am new to Hearthstone, but I am building up a Mage character all the way to level 10. At the end of many practice rounds, I have been granted additional cards for that character, like "Frost Nova".
However, I have played many subsequent games as the Mage, but these cards that I won, never ever show up. I have never had a card show up that lets me Freeze anything, even though I have won several such cards. Am I doing something wrong?