World gen templates are used to make your custom blocks spawn in a newly generated world. Custom blocks spawn in veins of a random amount of blocks. They may only spawn in a set list of biomes of worlds. Gen templates do also have more specific options that this wiki page will be overviewing.
**If you want custom blocks to spawn in your worlds, make sure you enable the `custom-blocks.enable-world-gen` option in the main MMOItems config file!**