System Mechanics: Item Recipes:

Any time that a character wishes to build something, they can either try to improvise something, or study from instructions.  Below are the chances of crafting a simple item, with each progressive stage of specialization adding an additional 1d10 added to the sum chance of difficulty per level of understanding of its natures that one is below it per nature the item has.  Those that have a greater understanding of an item's natures than is needed to wield it have 1d10 removed from the sum chance of difficulty per level of understanding they have in that nature, with zero or negative difficulty values allowing one to improvise creation of said item with any suitable materials and equipment, and sometimes even those that are not typically considered suitable by the general public.

Those that improvise have a 3d10 (sum) chance of crafting an item properly if they have the proper materials and equipment for each step and have a knowledge of the equipment and materials but not the crafting of the item itself.  Those that have a knowledge of the equipment but not the materials have a 4d10 (sum) chance of crafting the item properly per step, if they at least have the proper materials and equipment.  Those that have no knowledge of the equipment or materials but have the proper equipment and materials have a 5d10 (sum) chance of crafting the item properly per step.  Those have have neither knowledge of the equipment or materials and have the proper equipment but wrong materials have a 6d10 (sum) chance of crafting the item properly per step.  Those that have neither knowledge of the equipment or materials and have the wrong equipment and materials have a 7d10 (sum) chance of crafting the item properly per step.  Those that attempt to improvise crafting an item without even having an idea of what they are creating during a particular step have a 8d10 (sum) chance of crafting the item properly per step.

On the other hand, those that use instructions (or recipes, as they are called collectively) have 1d10 chance of crafting an item properly the first time if they have already created one item previously of each of its natures, and 2d10 (sum) chance of crafting an item properly the first time that they create an item without already having created one with all its natures already.

After creating an item correctly the first time, regardless of method, the character has a chance of remembering how they created it.  If it was in a combat situation or in an altered mental state, then they will have a WIL Check and/or Sanity Check needed to determine if their respective statistic and/or attribute is strong enough to recover that information properly.  If it was in a normal mental state out of combat, or if they have passed their checks, then their chance is the sum of their INT, WIL and WIS compared to a 2d10 (sum) roll by the GM for that specific recipe to become part of their knowledge.  Those that have low INT scores may later have difficulty pulling up that recipe without it being written down for reference, but the information would still be in their mind somewhere, waiting to be called upon when needed.  It is, however, recommended that characters do write it down for the benefit of other characters, especially those in their party, so that should anything happen to them later to make it difficult or impossible for them to pull up the information later, the recipe would still be known to someone else.