How should I modify the permissions? For example, I only want VIP players to use this skill.

        "Rain hellfire": {
          "Permission required to show this node": null,
          "Minimum prestige required to unlock this node": 0,
          "Minimum player level required to unlock this node": 0,
          "Skill required to unlock node [Requires max level]": null,
          "Skill that if unlocked, will prevent this node from unlocking": null,
          "enabled": true,
          "max_level": 1,
          "tier": 4,
          "value_per_buff": 1.0,
          "buff_info": {
            "Key": "Raiding_Ultimate",
            "Value": "IO"
          },
          "icon_url": "https://www.dropbox.com/s/tfn326c3pnhyri4/Raiding_Ultimate.v1.png?dl=1",
          "skin": 2929679053,
          "permissions": null

OK, thanks