faint walrusIt seems like there might be an issue with the resourcepack not being configured correctly. Ensure you have the resourcepack enabled, as it could cause issues with Herobrine's appearance. Also, verify that the mod resources are above Minecraft in the resourcepacks list if you're using Forge.
If nothing is happening after three in-game days, ensure the datapack is installed correctly. You can provoke Herobrine immediately by building a classic Herobrine shrine using mossy cobblestone or gold blocks as the center.
Additionally, make sure you have only the mod or the datapack enabled, as having both enabled might cause conflicts. If these steps don't solve the issue, you can modify settings through the in-game config using the command: /function fromthefog:admin/config. Let me know if you need further assistance!
vernal elk
sweet vine