Kingdoms of Amalur: Reckoning is an epic, open-world role-playing game set in Amalur, a mysterious and magical new fantasy world created by New York Times best-selling author R. A. Salvatore. Brought to life visually through the trademark visceral style of renowned artist and Spawn creator Todd McFarlane, Reckoning brings a new level of intense action combat to the RPG genre.
Go to: http://www.origin.com/us/about
Click "Download Origin" (from the upper left corner)
Login into downloaded application
Install and start application, login with your Account name and Password
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Redeem Product Code
From the "Origin" drop-down menu (upper right corner) choose "Redeem Product Code...",
enter your code and click "Next".
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After successful code verification go to the "MY GAMES" tab and start downloading.