look in Codex under Mythics. every time you use, convert, or salvage a Myth Stone, there is a chance to reveal part of a recipe, but the actual part of any recipe revealed is random. do a search on Skaul's tips and see if he has a list of the recipes. I just decided to wait until I had them revealed the hard way, by the time I was able to use them, a bunch of them were revealed. if you can't wait, just read the recipes in Skauls post.
4 different Myth stones make a Mythic affix, but u need a certain reciepe for each affix.