Vanalen Flowered Sandals is crafted with Tailoring in Mabinogi (shoes). This page lists everything needed to make it, checked against the game as it exists today. The interactive planner lives in the Tailoring Companion.
How to get the sewing pattern
The sewing pattern is rank 8 and survives 30 uses; every crafting attempt spends one use.
Eweca Orb (Sept. 2019): Break open an Eweca Orb from the web shop for a random reward.. Requires real-money web shop currency to buy the orb.
Sources that no longer exist: Production Gachapon (2012), Eweca Orb (2013).
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
1× Finest Fabric — weaving on a loom, higher rank
1× Fine Fabric — weaving on a loom, low rank
1× Braid — low-rank Weaving skill output
Finishing (once per item)
2× Fine Finishing Thread — Buy directly from any general goods NPC shop.