How do you make a button do something?

Like I want to script it.

EX: I pressed the "Play" button, and it deletes the message.

I know everything, but the ending part. (Last line) I want to know it.

-- Make sure this is in the button
Gui = Script.Parent.Parent.Parent --LOCATE THE WHOLE GUI HERE
function OnClick()
	Gui.Visible = false
end
script.Parent.MouseButton1Click:connect(OnClick)

--OR
Gui = Script.Parent.Parent.Parent --LOCATE THE WHOLE GUI HERE
function close()
	Gui:destroy()
end
script.Parent.MouseButton1Down:connect(close)

--EITHER OF THEM WORK. YOU ONLY NEED 1. Make sure this is the button's child