It took me some playing around to figure out what to do, but the loop is to ask your customer what they want and then you go draw up a plan at the blueprint table guessing what they want from your conversation. Then grab it from the oven, hammer it, and cool it down. Then sell it to your customer. You'll see how close you were.
I'm not sure if the numbers really make sense from what they are asking for though. One time I was comparing and remembering what they asked for and then the "customer wanted" numbers totally changed while the dialog was up.
I'm not sure if it's possible to fail, the game just kept going. Really interesting idea to run around and be a blacksmith though for custom swords!