you can learn this skill at Jewelry(open your mini-map in DaLi LuoYang or SuZhou, you can see the word Jewelry)
you do not need to craft things to level the skill, which means you can level the skill if you have enought experiment, gold and level requirment
with crafting skill you can make rings, necklaces, or amulets
to craft anything you will need the corresponding ore, jade and design(level 1-4 designs can be brought in DaLi LuoYang or SuZhou, level 5 designs are in West Liao, and level 6 plans are in Crocodile Island)