Generating Custom Configured and Placed Features

I'm trying to make a new dimension with some new biomes in it and I want each biome to have some funky tree-like structures or random (big or small) rocks. I've made a few structure files that I want to use but I keep running into errors like:  Unknown registry key: minecraft:structure or Detected setBlock in a far chunk, status: minecraft:features, currently generating: ResourceKey[minecraft:worldgen/placed_feature / eds_dim:test]