I currently have two main ideas for how this could work.
Idea 1: MC-Style Crafting
Instructions could just be a way to discover/unlock crafting recipes, with a workbench or work area allowing the user to craft whatever it is from a kit (or separate items in a kit).
Idea 2: Subnautica-Style Crafting
Instructions are the key to making things, without them you cannot craft. There are no "crafting recipes", but rather you use the instructions and the kit materials to "assemble" the item (the time this takes might be less as you level up if future RPG ideas take shape). Without instructions, you cannot assemble things.