i wanted to make gui visible by a button it didnt work. Can someone help?

You changed the StarterGui Guis. StarterGui guis are only viewable by server and what we see is PlayerGui. Heres a sample below:

game.Players.Thelodomir_320.PlayerGui.ScreenGui.Frame.Visible = true

To fit in your script, you need to access to PlayerGui. By accessing PlayerGui you need to have the player. You can get player parameter with PlayerAdded event. You can access it with any script.

game:GetService("Players").PlayerAdded:Connect(function(player) -- to get the player parameter
    local Brick = script.Parent
    local Sound = Brick.Sound

    function onClicked()
        Sound:Play()
        player:WaitForChild("PlayerGui").ScreenGui.Frame.Visible = true
    end

    Brick.ClickDetector.MouseClick:Connect(onClicked)
end)

Hm. Well I say i have the solution for that.

You did the sound and the playing sound wrong.

Brick = script.Parent.Brick.Sound


local function OnClick()
    Brick.Playing = true
    game.StarterGui.ScreenGui.Frame.Visible = true
end

script.Parent.ClickDetector.MouseClick:Connect(onClicked)

not

Brick = script.Parent Sound = Brick.Sound

function onClicked() 
    Sound:Play() game.StarterGui.ScreenGui.Frame.Visible = true 
    game.StarterGui.ScreenGui.Frame.Visible = true
end

script.Parent.ClickDetector.MouseClick:connect(onClicked)