How do i make a Dissapearing Gui?

Use the code blocks for code, and don't bother doing the line numbers. the code block does it for you.

Answer:

All Gui objects (except the Guis themselves) have a bool property called Visible. So:

button.MouseButton1Down:connect(function()
    frame.Visible = false
end) -- also, these types of functions have a ')' after the end

Also, you need to define everything (like the button) that you will use in the script.

Answer : The button and the frame are not defined so

button = script.Parent --Make sure that the script is in the button
frame = script.Parent.Parent.FrameName --Replace the name of the frame here
button.MouseButton1Click:connect(function()
frame.Visible = false
end

If you would like it to reappear when they click it again, then

button = script.Parent
frame = script.Parent.Parent.FrameName -- Replace the name of the frame here
function onClicked()
if frame.Visible == true then
    frame.Visible = false
else
    frame.Visible = true
end
button.MouseButton1Click:connect(onClicked)

It's as easy as that

Here:

local b=script.Parent
local fr=script.Parent.Parent.Frame -- Replace Frame with the Frame's name
b.MouseButton1Down:connect(function()
    fr.Visible=not fr.Visible
end)