During the game you will need to seek the crafting diagrams to become on expert on it. In the witcher 2 assassins of kings enhanced edition you will locate the crafting diagrams below. Follow the complete guide below to collect all the diagramsthat you need. The items can only be crafted with the help of craftsmen who will collect the fee for their work. The Craftsmen can be found in towns and villages, especially in their central sections, among other traders. Don’t forget to pay them as their work is one of a kind.
Okay not that simple to get the crafting but all you need to do is purchas from traders, though you may also find them lying about for the taking. All the Crafting components can be purchased from traders or found in various locations through out the game. As you collect all the diagram  then you will need to locate craftsman.
Witcher 2 Assassins of Kings Crafting Diagrams Location Guide