How do i add a cooldown script that informs player when he can click again?

Hi. I have managed to msg player when player clicks to get item if player already have that item in inventory but i have no idea how to add a cooldown on it instead of checking backpack.

Hope someone can help me change from this to cooldown timer for player (I would wish to have option to do it for all players and option for only player that have clicked. If not possible then only for player who clicked)

NOTE: I'm a compleete noob in scripting

function onClicked() do
					--for i=1, 1 do
					--while wait(5) do

		for _, player in ipairs(game.Players:GetPlayers()) do

			if player:FindFirstChild("Backpack") then
				if player:FindFirstChild("Backpack"):FindFirstChild("Blue Master Key")
				or
				player:FindFirstChild("Backpack"):FindFirstChild("Green Master Key")
				or
				player:FindFirstChild("Backpack"):FindFirstChild("Red Master Key")
				or				
				player:FindFirstChild("Backpack"):FindFirstChild("Yellow Master Key")
				then
				local M = Instance.new("Hint")
				M.Parent = game.Workspace -- Don't edit or change this.
				M.Text = "You allredy own a Master Key"
				wait(3) -- Wait to change insert thing.
				M.Text = "You can only have 1 Master Key in your inventory"
				wait(3) -- Waits to change then Remove insert differ thing.
				M:Remove()
						else do
------HERE GOES VERRY HUGE SCRIPT
end
end
end
end
end
end
end
end
end
end
--------------------------------------------------------------------
script.Parent.ClickDetector.MouseClick:Connect(onClicked)

hello, kexiGamer!

This just adds a debounce to your code!

local deb = false
function onClicked() do
	if not deb then
	deb = true

	for _, player in ipairs(game.Players:GetPlayers()) do

            if player:FindFirstChild("Backpack") then
                if player:FindFirstChild("Backpack"):FindFirstChild("Blue Master Key")
                or
                player:FindFirstChild("Backpack"):FindFirstChild("Green Master Key")
                or
                player:FindFirstChild("Backpack"):FindFirstChild("Red Master Key")
                or              
                player:FindFirstChild("Backpack"):FindFirstChild("Yellow Master Key")
                then
                local M = Instance.new("Hint")
                M.Parent = game.Workspace -- Don't edit or change this.
                M.Text = "You allredy own a Master Key"
                wait(3) -- Wait to change insert thing.
                M.Text = "You can only have 1 Master Key in your inventory"
                wait(3) -- Waits to change then Remove insert differ thing.
                M:Remove()
                        else do
------HERE GOES VERRY HUGE SCRIPT
end
end
end
end
end
end
end
end
end
end
wait(120) -- Cooldown
deb = false
end
--------------------------------------------------------------------
script.Parent.ClickDetector.MouseClick:Connect(onClicked)

This Cooldown is called debounce

This script shows countdown:

local deb = false
local CountdownTime = 120 -- You can change the countdown time =D

-- Don't change above!
local Countdown = CountdownTime
local Text = script.Parent.Text
function onClicked() do
    if not deb then
    deb = true

    	for _, player in ipairs(game.Players:GetPlayers()) do

            if player:FindFirstChild("Backpack") then
                if player:FindFirstChild("Backpack"):FindFirstChild("Blue Master Key")
                or
                player:FindFirstChild("Backpack"):FindFirstChild("Green Master Key")
                or
                player:FindFirstChild("Backpack"):FindFirstChild("Red Master Key")
                or              
                player:FindFirstChild("Backpack"):FindFirstChild("Yellow Master Key")
                then
                local M = Instance.new("Hint")
                M.Parent = game.Workspace -- Don't edit or change this.
                M.Text = "You allredy own a Master Key"
                wait(3) -- Wait to change insert thing.
                M.Text = "You can only have 1 Master Key in your inventory"
                wait(3) -- Waits to change then Remove insert differ thing.
                M:Remove()
		else do
------HERE GOES VERRY HUGE SCRIPT
end
end
end
end
end
end
end
end
end
else
	script.Parent.Text = "Can't click now, must wait: " .. Countdown .. " seconds!"
	wait(5)
	script.Parent.Text = Text
end
while Countdown > 0 do
	Countdown = Countdown - 1
end
local Countdown = CountdownTime
deb = false
end
--------------------------------------------------------------------
script.Parent.ClickDetector.MouseClick:Connect(onClicked)

Hope it helps!

Good Luck with your games!

I believe what you're looking for is debounce: https://wiki.roblox.com/index.php?title=Debounce

I added it into your script, hopefully this is what you want and it works out for you.

I also indented your code to make it look neater and see that you have unnecessary ends that don't add up at the end.

local buttonPressed = false
function onClicked() do
		--for i=1, 1 do
		--while wait(5) do
		if not buttonPressed then
			buttonPressed = true
			for _, player in ipairs(game.Players:GetPlayers()) do
				if player:FindFirstChild("Backpack") then
					if player:FindFirstChild("Backpack"):FindFirstChild("Blue Master Key")
						or
						player:FindFirstChild("Backpack"):FindFirstChild("Green Master Key")
						or
						player:FindFirstChild("Backpack"):FindFirstChild("Red Master Key")
						or              
						player:FindFirstChild("Backpack"):FindFirstChild("Yellow Master Key")
						then
						local M = Instance.new("Hint")
						M.Parent = game.Workspace -- Don't edit or change this.
						M.Text = "You allredy own a Master Key"
						wait(3) -- Wait to change insert thing.
						M.Text = "You can only have 1 Master Key in your inventory"
						wait(3) -- Waits to change then Remove insert differ thing.
						M:Remove()
						buttonPressed = false
					else do
							------HERE GOES VERRY HUGE SCRIPT
						end
					end
				end
			end
		end
	end
end
--------------------------------------------------------------------
script.Parent.ClickDetector.MouseClick:Connect(onClicked)