function Click() Game.StarterGui.Music.SoundId = "rbxassetid://142478510" Game.StarterGui.Music:Play() wait(120) Game.StarterGui.Music.SoundId = "rbxassetid://142478390" Game.StarterGui.Music:Play() end script.Parent.MouseButton1Down:connect(Click)
The StarterGui is just a container for GUI objects. When a player spawns, the items in StarterGui are copied into the player's PlayerGui. So if you play a Sound in StarterGui, no one will hear it.
Assuming this is a LocalScript, and you put it inside your GUI, you should be playing the "Music" sound object that exists in the script's parent.
e.g.
local music = script.Parent.Music music.SoundId = "rbxassetid://142478510" music:Play()