try this one

groups:
  default:
    permissions:
    - essentials.break.*
    - essentials.chat.*
    - essentials.build.*
    - modifyworld.*
    - kit.spawn.starter
    - factions.join
    - factions.kick
    - factions.description
    - factions.unclaimall
    - factions.name
    - factions.disband
    - factions.unclaim
    - factions.claim.radius
    - factions.claim
    - factions.title
    - factions.player
    - factions.faction
    - factions.home
    - factions.demote
    - factions.create
    - essentials.sethome
    - essentials.home
    - essentials.spawn
    default: true
    worlds:
      Factions:
        default: false
  Coal:
    inheritance:
    - default
    permissions:
    - kit.spawn.Coal
    prefix: '&0[Coal]'
  Iron:
    inheritance:
    - Coal
    permissions:
    - kit.spawn.Iron
    - essentials.feed
    prefix: '&7[Iron]'
  Gold:
    inheritance:
    - Iron
    permissions:
    - kit.spawn.Gold
    - essentials.workbench
    prefix: '&e[Gold]'
  Diamond:
    permissions:
    - modifyworld.*
    - kit.spawn.Diamond
    - essentials.ptime
    inheritance:
    - Gold
    prefix: '&b[Diamond]'
  Emerald:
    prefix: '&a[Emerald]'
    inheritance:
    - Diamond
    permissions:
    - kits.spawn.Emerald
    - essentials.fly
  Admin:
    inheritance:
    - Emerald
    permissions:
    - essentials.gamemode
    prefix: '&4[Admin]'
  Head-Admin:
    permissions:
    - '*'
    prefix: '&9[HeadAdmin]'
  Owner:
    permissions:
    - '*'
    prefix: '&6[Owner]'
users:
  29b90e1e-216c-4856-9233-b3d64d3776e9:
    group:
    - Owner
    options:
      name: CraigTheMailman