The article mentions some resources in the Engine and Learning Materials sections.
He learned by following tutorials for Corona SDK[1] for a couple months, learning what he could of Lua[2] and making a very simple game.
Then, he switched to Cocos2D[3] and had to learn Objective-C and Xcode. He bought the books Programming in Objective-C[4] and Learning Cocos2D[5] and started reading and coding.
He also regularly visited the Cocos2D forums[6] and Ray Wenderlich's site[7] to solve problems as they came up.
He learned by following tutorials for Corona SDK[1] for a couple months, learning what he could of Lua[2] and making a very simple game.
Then, he switched to Cocos2D[3] and had to learn Objective-C and Xcode. He bought the books Programming in Objective-C[4] and Learning Cocos2D[5] and started reading and coding.
He also regularly visited the Cocos2D forums[6] and Ray Wenderlich's site[7] to solve problems as they came up.
[1]: http://www.coronalabs.com/
[2]: http://www.lua.org/
[3]: http://www.cocos2d-iphone.org/
[4]: http://www.amazon.com/dp/032188728X/
[5]: http://www.amazon.com/dp/0321735625/
[6]: http://www.cocos2d-iphone.org/forums/
[7]: http://www.raywenderlich.com/