Refined Dustin Silver Knight Helm is crafted with Blacksmithing in Mabinogi (helmet). This page lists everything needed to make it, checked against the game as it exists today. The interactive planner lives in the Blacksmith Companion.
How to get the manual
The manual is rank 3 and survives 30 uses; every crafting attempt spends one use.
Hard Mode Dungeons: hardmode end-chest drop, rare unique manuals not sold anywhere else. Find the second lobby behind the normal dungeon lobby and drop any item, up to 8 players.
Materials
Expect about 3 attempts per finished item (35% average progress per attempt). Per-attempt materials are consumed on every attempt; finishing materials once per item.
Each attempt uses
3× Phantasmal Ingot — crafted product, no gather/drop method exists
1× Soft Fur Fabric — Weaving production from Soft Fur Pelt (Wing-eared Rabbit drop or part-time job)
15× Lightless Metal Fragment — Elite Shadow Missions / Advanced Hardmode Dungeons drop