Put your Blockbench file here:

  sand-castle/source/sand_castle.bbmodel

Rename your file to sand_castle.bbmodel if it has a different name.

Minecraft does NOT use the .bbmodel file in-game.
Keep it here so you can edit later, then export to:

  custom-mob-resource-pack/assets/v3719/models/item/sand_castle.json

See sand-castle/README.md for full steps.
