How to Earn your Hero:
Just play Heroes of the Storm – Free. it’s as simple as that! Anyone who logs into Heroes after our next major patch goes live on September 13 will be met with a new popup asking them to claim their reward. Choices will be final, so take some time to look over your options using the detail screen provided for each Hero before locking in your decision.
Who Can I Choose Free ?
KONTAK PERKASA FUTURES – Everyone will be given a choice between three Heroes to begin with – Tyrande, Anub’arak, and Thrall. If you already own any of these Heroes, they will be replaced with Nazeebo, Sonya, and Uther, in that order. If you already own all six of these Heroes, we will grant you their equivalent value in Gold (4,000)! All of the free Hero choices have the same Gold and real money value, so don’t worry about trying to find the best bang for your buck, just choose the Hero that you want to play!
We hope you’ll enjoy this new addition to your Hero roster. We’ll see you (and your new Hero) in the Nexus, soon!
Source : heroesofthestorm.com