How do I make a part that makes a sound when you click it?

What you'll need for this is a ClickDetector, which will fire an event when the player clicks on it. Simply connect a function to the event, and the function will be ran whenever the event is fired. Also take note of the method named FindFirstChildOfClass, which finds the first child of the given type, in this case Sound. After we've gotten the sound, we can simply call its Play method whenever we want to play it.

--This code is in a Script, which is in the desired part.
local clickDetector = Instance.new("ClickDetector")
clickDetector.Parent = script.Parent
local sound = script.Parent:FindFirstChildOfClass("Sound")
clickDetector.MouseClick:Connect(function()
    sound:Play()
end)

put a click detector object inside of the part and use the click detector clicked event

--function that gets called whenever the clickdetector gets clicked:
game.Workspace.PartNameHere.ClickDetector.MouseClick:Connect(function()
    game.Workspace.Sound:Play() --play sound
end)

Here's a tutorial about events: https://www.youtube.com/watch?v=oAnWzxol4e8 I'd recommend watching the whole series since you're knew. It's a good resource.