Skinning of textfields/alertboxes/windows

Last time I stopped working with Corona was not because of the game mechanics because those were awsome and easy to use… I stopped because i couldnt figure out how to skin all these GUI stuff.

Is there some documentation/explanation. Even the documents or books/videos that you have to pay for are good…

Because as developer I/We suck at making graphics but buying graphics is easy…now just need to know how to implement them :smiley: