Hey there. There are some great scripts out there to add blacksmithy/alchemy functions and whatnot to your game but this is for anyone out there who has either a technical phobia of scripts or is just more comfortable with events
I have seen this done in newbie tutorials with Choices but the flaw with this event method is simple; you have to have some kind of NPC or event to interact with, and you can only have three or four options! "Sword, Shield, Potion" Etc. This is silly and limiting.
The way I've done it is using interactable items that act as "recipes". You could call them instructions, plans, books, or whatever is relevant to your game.
I'm going to use a simplified Lemonade as an example in this tutorial.
Make the items you need in the database. So, you will need the ingredients, the finished item, and the recipe, so this is what you'd see in your database;
Lemon
Glass Bottle
Sugar
Lemonade
Lemonade Recipe
Now, make the Lemonade Recipe call a Comment Event, and make it so that it is not consumable (unless you prefer otherwise).
Go to the Common Events tab and make a set of conditional branches checking the ingredients, and add or remove items as nessessary, with any messages/sound effects you desire to express your success or failure;

And there you have it. I prefer this much more to making NPC's with Choices and your character is able to interact with the Recipe wherever they are, and collecting recipes along the way can add a fun factor.
Forgive me if I dissapear months at a time... It's exam season yo D:
I'm working on a game called The Goblin Queen, I'll post a demo soon!