{
  "name": "additionalstructures:example",                       <= pool name
  "fallback": "minecraft:empty",                                <= almost always "minecraft:empty"
  "elements": [
    {
      "weight": 1,                                              <= weight
      "element": {
        "element_type": "minecraft:single_pool_element",        <= empty_pool_element (placing nothing), feature_pool_element (placing a placed feature), legacy_single_pool_element, list_pool_element, and single_pool_element (placing a structure)
        "location": "additionalstructures:example_structure",   <= path of the structure.nbt file
        "projection": "rigid",                                  <= Either rigid or terrain_matching. Use the latter if you want the structure to match the terrain, just like village paths do
        "processors": "minecraft:empty"                         <= ?
      }
    }
  ]
}
