Choose whether to purchase the Steam key or the stand-alone launcher key. If you opt for the stand-alone key, it will be automatically activated on your account.
Start the launcher, it will ask you to register with an e-mail and password or use an existing social network account.
On the left side in your launcher, you will see the Redeem button. Click on it and enter the single key for the Adventurer Pack. If you purchased the Hero, General or High Warlord Pack, enter the one key and redeem it. Repeat the redemption process with the second key to unlock the additional content.
Now click on Install and the game will be downloaded and installed. Once the installation process is complete, you can click on Play.