In the case of Knowledge Rolls, Tagan, you'd just roll a 1d20+3.  Knowledge Checks work a bit differently in Fantasy Craft.  Basically, there's no such thing as being trained or untrained in a specific field of knowledge.  So if you believe your character has a reasonable chance of knowing something, you may make a roll.  If any additional modifiers come into play (ie: If you're rolling for information on local wildlife, you might get a +2 to the roll from having Knowledge: Nature as a study), I'll let you know.