Can anyone tell me how to craft set armour

I'm curious what is needed to craft set armour?  How do you get the recipes for them and what is needed?

Set armors are done at various crafting stations located through out the world - I'm sure there is a list of them somewhere. 

They have requirements - the first couple that I know of in Stonefalls needs you to have researched 2 trait lines in the armor pieces you wish to craft.  Since they are only 3 piece sets it only requires 2 traits researched on three pieces of armor for you to craft the set. 

Not only do the number of traits that you need to research go up but also the number of pieces that you need researched go up since some are 5 piece sets and some are full sets.  Some sets require you to have 7 or 8 traits researched on 7 pieces of armor - but they are pretty epic sets.  ...and you still have to locate these crafting stations out there in the world.

Found a link for you that explains it better and gives the locations and the sets:

http://tamrieljournal.com/crafted-item-sets-eso/

There are also set armors you can't craft. Notably the popular ones in L15-20 is the Warlock and Dragon sets. Those are drops with varying green and blue drops ranging L15-20.