Bianca Drawers Layered Skirt is crafted with Tailoring in Mabinogi (clothes). 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 6 and survives 30 uses; every crafting attempt spends one use.
Fleta: Buy a pattern from Fleta while she wanders Sen Mag Plains near the crossroads. (92,000 gold). She only appears at set morning, afternoon, and evening windows.
Solea Chest: Open a treasure chest in the Solea caves using a Treasure Chest Key.. Requires a Treasure Chest Key, a rare drop from monsters in Solea.
Materials
Expect about 4 attempts per finished item (30% average progress per attempt). Per-attempt materials are consumed on every attempt; finishing materials once per item.
Each attempt uses
2× Finest Silk — weaving on a loom, higher rank
2× Fine Leather — fragmentation of Fine Leather Strap (or weaving byproduct)
1× Finest Leather Strap — weaving rank 3-1 on a spinning wheel
Finishing (once per item)
1× Finest Finishing Thread — Buy directly from any general goods NPC shop.
1× Youthful Black Perfume — Drops from Black Succubus monsters or comes from Fashion Gachapon capsules.
1× Magical Silver Thread — Synthesize Silver Ore, Common Fabric, and Common Silk at Synthesis rank 9.