Short answer
The organ is built during Organic Music, a quest from Harold the woodcarver that opens after Still Standing on Stilts. Find the woodcarvers at the Stilt Houses, bring Harold 2 Building Kit I and 1 Iron Kit II to fix his wood-catching machine, then build the Organ in the Church from 4 Special Wood and 6 Steel Detail. Tell Agatha at the Crossroads and Herbert at the Barracks to finish.

The graveyard
View full-size image ↗Official promotional screenshot · © Lazy Bear Games / tinyBuild · Official media kit · Material credits
Step by step
1. Find the woodcarvers in the Stilt Houses.
2. Bring Harold 2 Building Kit I and 1 Iron Kit II so he can repair his wood-catching machine.
3. Build the Organ in the Church using 4 Special Wood and 6 Steel Detail.
4. Talk to Agatha at the Crossroads about the new church organ.
5. Tell Herbert at the Barracks that the organ is built.
The Iron Kit II catch
Iron Kit II is not on the basic Smithy. It needs Smithy II with the Bellows upgrade: 1 Iron Ingot + 2 Clay Molds makes 4 kits, at Smithing mastery 5.
Our iron kit guide covers both kit tiers.
Special Wood and steel
Harold only sells Special Wood after his machine is fixed in step 2 — our special wood guide lists his prices.
Steel Details need Steel Ingots, which the Bishop at the Royal Foundry sells.

The Town harbour from the official media kit. Harold works out of the Stilt Houses; this is not his workshop.
View full-size image ↗Official promotional screenshot · © Lazy Bear Games / tinyBuild · Official media kit · Material credits
Rewards and what it opens
The quest pays 6 Town Gratitude across its steps.
It leads to The House at the Crossroads (with See You in Church) and then A Good Example is the Best Sermon.
That chain ends with the An Unlikely Pair achievement, when Agatha and Herbert find common ground.
Sources
- communitywikily.gg — Organic Music
- communitywikily.gg — Iron Kit II
- communitywikily.gg — Achievements
Related pages
Official screenshot · © Lazy Bear Games / tinyBuildCraftingGraveyard Keeper 2 Special Wood
Official screenshot · © Lazy Bear Games / tinyBuildCraftingGraveyard Keeper 2 Iron Kit I & II
Official screenshot · © Lazy Bear Games / tinyBuildProgressionGraveyard Keeper 2 Choir
Official screenshot · © Lazy Bear Games / tinyBuildThe TownGraveyard Keeper 2 Herbert
Official screenshot · © Lazy Bear Games / tinyBuildEconomyGraveyard Keeper 2 Town Gratitude
Official screenshot · © Lazy Bear Games / tinyBuildThe TownGraveyard Keeper 2 Harold