MineOS in FreeNAS jail Forge Modpack

I am a complete beginner when it comes to Servers. I have managed to set up and successfully run a vanilla server.
My problem comes when trying to install Enigmatica 2 mod pack. I have followed multiple tutorials, i have read post after post and are extremely lost. I am not sure if it is a permission thing within the jail or what?

Any help or step by step guide would be greatly appreciated.