How to Craft and Place a Coffin
Pick your wood
Coffins come in every overworld wood type: Acacia Coffin, Bamboo Coffin, Birch Coffin, Cherry Coffin, Crimson Coffin, Dark Oak Coffin, Jungle Coffin, Mangrove Coffin, Oak Coffin, Spruce Coffin, and Warped Coffin. Each is a shaped crafting recipe built from its matching planks, so gather the wood you want and craft the coffin at a crafting table.
Place and use it
Set the coffin down on a solid block. It occupies space like a bed and is meant to be a resting container for a body. Place coffins in rows inside a crypt, Ossuary, or Sarcophagus room to build a burial hall. Because each coffin is a full block entity, leave a gap between rows so you can walk between them.
Match the theme
Pair wood coffins with matching gravestones nearby — for example an Oak Coffin beside a Cobblestone Gravestone, or a Dark Oak Coffin beside a Deepslate Gravestone. For a nether-themed room use Crimson Coffin or Warped Coffin with Polished Basalt Gravestone or Cracked Polished Blackstone Gravestone. For a desert build, use Sandstone Gravestone or Red Sandstone Gravestone next to a plain wood coffin.
Fill a room
A simple crypt: a floor of stone, walls of Dark Iron Block, a Dark Iron Door for the entrance, and a line of coffins down the center. Add a Candle Holder or Fire Brazier at the head of each coffin for light. This gives you a complete, walkable burial chamber using only blocks from the mod.