Mode is optional, will filter the game mode: Dragons, DragonEscape or DragonsTeams. Otherwise will show all modes.
You can set to show or not show an arena on the menu if the player cannot join the game by setting Options.Game-Menu-Show-Only-Available-Arenas to true.
You can edit menu items at Items.Join-Arena-Item and Items.Cannot-Join-Arena-Item
You can change the Menu name and Item lore at Messages.Menus.Join-Menu-Name, Messages.JoinMenu.Item-Lore