Convert OnClick brick to OnClick TextButton?

So ive got this script that atm runs on an OnClicked Brick so when u click the brick it starts my dice rolling game. But im wanting to convert to it to a GUI system instead of through a brick, but im lost on how to do this, here is what ive got

The part im hung up on (i think)

    part = clicked.Character.Head
	local h = part.Parent:findFirstChild("Humanoid")

This script is a product of help from other community members when i was using it for something else, and this part was added to make it work, but this is for a "Part" within workspace, idk how to change it for a GUI within startGui, idk if this matters but figured i would throw it in.

function onTouched(clicked)
    part = clicked.Character.Head
	local h = part.Parent:findFirstChild("Humanoid")
	if (h~=nil) then
			local thisplr = game.Players:findFirstChild(h.Parent.Name)
			if (thisplr~=nil) then
				local stats = thisplr:findFirstChild("leaderstats")
				if (stats~=nil) then
					local score = stats:findFirstChild("Gold")
					if (score~=nil) then
						local Dice = game.Players.Player.PlayerGui.Roller.TextLabel
						local Rolls = math.random(100)
						for _ = 1, 1 do
							
							print(Rolls)
							if Rolls >= 55 then
								score.Value = score.Value + 1
								Dice.Visible = true
								Dice.Text = ("You rolled a ") .. Rolls .. ("!")
								wait(2)
								Dice.Visible = false
							else
								Dice.Visible = true
								Dice.Text = ("You rolled a ") .. Rolls .. ("...") 
								wait(2)
								Dice.Visible = false
							end
							wait(.1)
						end

					end
				end
			end
		end
	end

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

Any help steering me in the right direction is appreciated :)