Does anyone know how to make a button and when you press the button a decal pops up on a part?

So, I can't find how to make this type of script. I have tried using the function onClick, but that is not working. I think i have to group the models together, but that does not work either. If anyone could be kindful could you please share your script with me. Thank You So Much! Bye! :)

Don't request stuff on scripting helpers. But here's an example

I have a two parts. One named Button and one named Screen

This script is in the button. The script creates a decal on the part named Screen

local Button = script.Parent
local Screen = Button.Parent.Screen
local ClickD = Instance.new('ClickDetector', Button)

ClickD.MouseClick(function()
local Decal = Instance.new('Decal', Screen)
end)