my script seems fine but has an error. someone help?(sound doesnt play when i click)

so theres a menu gui, and this script is inside the play button.

a sound is playing.

how can I make it so if I click, the r2dm sound stops and the other sound plays?

if you want to help me, make sure the sound stops and r2dm plays if the player dies. thanks.

local song = script.Parent:WaitForChild("Sound") --normal song
local menus = script.Parent:WaitForChild("R2DM") --menu song

menus:Play()

function onClicked(GUI)
	menus:Stop()
	song:Play()
end
script.Parent.MouseButton1Click:connect(OnClicked)

Your script is correct, however on line 10 you connected OnClicked, starting with a capital, but you defined your function as onClicked, starting with a lowercase. Lua is case-sensitive.

Also, use Connect instead of connect because the latter is deprecated.

Final note, I highly recommend indenting your code, it makes it much easier for you and everyone else to read.

By indenting I mean having a tab space in front of every line that inside a child block:

-- NON INDENTED
function onClicked(GUI)
menus:Stop()
song:Play()
end

-- INDENTED
function onClicked(GUI)
	menus:Stop()
	song:Play()
end

The indented block is much easier to read and understand.