Do you mean alchemy? Is it is what you mean then:

Alchemy is a life skill that you may use to create your own equipment (weapons, armor, etc...). At first, you get primary alchemy (the most basic of alchemy) and you can actually turn it into junior and senior for better equipment. There are many topics on alchemy here on wlodb. You can scan around and it would help you out.

I suggest you start with this thread for basic knowledge: http://wlodb.com/topics/829