JoinSystem

on join:
 if player is op:
  broadcast "&7[&a+&7]%player%"
 else:
  broadcast "&7[&b+&7]%player%"
  teleport player to location at (0, 4, 0)
  format slot 4 of player with snowball named "&b参加&7(Right Click)" to close

command /givejoin:
 permission: skript.admin
 trigger:
  format slot 4 of player with snowball named "&b参加&7(Right Click)" to close

on rightclick with snowball:
 cancel event
 name of held item contains "&b参加&7(Right Click)"
 send "&7参加しました"