Earned cards never show up in my deck

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?

Solution 1:

The basic decks only contain the cards you start with. When you unlock cards from leveling up, they aren't automatically added. You need to build a new deck containing those cards.

To do this, go to "My Collection" and click "New Deck".

Solution 2:

They are in your collection. You have to make a deck that includes those cards.

There are preconstructed decks for every character, which is what you are using.