Lion Claw Lance is crafted with Blacksmithing in Mabinogi (weapon). 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 5 and survives 30 uses; every crafting attempt spends one use.
Giant Lion: field boss in Courcle's meadows, spawns twice daily.
Lileas: Jousting Arena Manager in Tara. Trade Jousting Points at her shop for manuals. Spend Jousting Points at Lileas's shop by the Tara jousting arena, earned from matches there.
Materials
Expect about 4 attempts per finished item (25% average progress per attempt). Per-attempt materials are consumed on every attempt; finishing materials once per item.
Each attempt uses
4× Iron Ingot — refine from Iron Ore (common low-rank Refining output)
4× Silver Ingot — refine from silver ore. Mine it in Barri Dungeon or north of Tory Ravine
4× Mythril Ingot — refine from mythril ore. Barri Mythril Mine/Advanced, or L-Rod ore deposits