The Biome Radar is a multiblock structure that helps you find biomes in the world.
First, you have to actually build the structure:
Then, insert a Biome Crystal. There's one for each Biome in the game, and they can be found in basically any chest with loot.
If the biome exists in the world, the fires on top of the Iron Bars will start blowing in its direction. If that's not enough, you can use a Location Filter on it to set it to the biome's location.
With that, you can craft it with a Golden Compass to make your way there!
