How do I make a SurfaceGUI text button activate this script when the button is clicked on?

So I'm trying to make a game where clicking on a button on a part starts a script.

My script that activates when the button is clicked:

local dup = game.Workspace
local T = .5
local size = Vector3.new (5,5,5)

function REP ()
    while true do
        local part = Instance.new("Part", dup)
        wait()
        part.Anchored = false
        part.Transparency = T
        part.BrickColor = BrickColor.new ('Baby blue')
        part.Reflectance = T
        part.Material = ("Glass")
        part.Size = size
        if wait == 0 then
            part.Anchored = false

        end
    end
end

REP()

How do I script a surfaceGui textbutton to run this script when clicked on?