Identify the loader explicitly
Read the launcher profile or server startup information and write down the loader name exactly. Confirm both the Minecraft version and the NeoForge version before searching the official Clumps downloads.
Use file metadata
Choose a file that explicitly lists NeoForge and the game version you run. Do not decide from a similar-looking filename alone. Review release notes and dependency information, then stop the instance before copying the jar into its mods directory.
Verify the result
Restart the same instance and keep its startup log. When troubleshooting, report the complete jar filename alongside your loader and Minecraft versions. Try a short session in a test world before opening a long-running survival world. This gives you a small, repeatable check and keeps installation problems separate from changes elsewhere in your mod collection.
Next step: read the installation guide or find a matching download.
Project reference: Official Clumps project and file details.