On the mod's product page, find and download the mod file, which should be compatible with Forge 1.20.1 as of now. Copy and paste the mod files into the "mods" folder in the root Minecraft directory.

For those looking for Minecraft biome mods, these are without a doubt the best out right now. Updated on August 14, 2024, by Ben Painter: The 1.21 Minecraft update has been out for some time now.