Arena Invitations | Shows the use of remote events to provoke all the clients

Arena.lua

game.ReplicatedStorage.JoinArena.OnServerInvoke = function(plr) 
	if plr:FindFirstChild("Arena") == nil then
		Instance.new("BoolValue",plr).Name = "Arena"
		plr.ChildRemoved:Connect(function(child)
			if child.Name == "Arena" then
				local amount = 0
				local theWinner 
				for _,player in pairs(game.Players:GetPlayers()) do
					if player:FindFirstChild("Arena") then
						amount = amount + 1
						theWinner = player
					end
				end
				if amount <= 0 then
					game.ReplicatedStorage.GuiReplicator:FireAllClients("WinnerAnnounce", "Nobody")
					wait(10)
					game.ServerStorage.ArenaBeingUsed.Value = false
				elseif amount == 1 then
					game.ReplicatedStorage.GuiReplicator:FireAllClients("WinnerAnnounce", theWinner.Name)
					wait(50)
					game.ServerStorage.ArenaBeingUsed.Value = false
				end
			end
		end)
	end
end

repeat
	wait(20)
	if not game.ServerStorage.ArenaBeingUsed.Value then
		game.ReplicatedStorage.GuiReplicator:FireAllClients("ArenaInvitation")
		wait(10)
		for _,player in pairs(game.Players:GetChildren()) do
			if player:FindFirstChild("Arena") then
				for _,cock in pairs(workspace.Chickens:GetChildren()) do
					if cock.Owner.Value == player.Name and not cock:FindFirstChild("Chicken") then
						Instance.new("BoolValue", cock).Name = "Chicken"
					end
				end
				game.ServerStorage.ArenaBeingUsed.Value = true
				game.ReplicatedStorage.GuiReplicator:FireClient(player, "ArenaInstructions")
			end
		end
	end
until game == nil

local part = Instance.new("Part",workspace)
part.Position = workspace.WideArena.Cam1.CFrame.LookVector * 10

game.Players.PlayerAdded:Connect(function(plr)
	local char = plr.Character or plr.CharacterAdded:Wait()
end)