You can use the in-game Codex to find the original items I used to craft. For example, if you look at the Flintlock I used, it’s called “Immortal Flintlock”. Search the Codex for the item, and you can see where to look for it. Once you’ve found the item, you need to “craft” it accordingly.
You can refer to this guide if you’re new to crafting
Rubik’s Crystallography