How do I make a gui show the tool the character is holding?

So far, I have this, it's a local script to a gui, but how would I be able to make it to where it shows the tool that the character is holding?

module3D = require(script.Parent.Module3D)
frame = script.Parent.Frame
guy = workspace.item

model3D = module3D:Attach3D(frame,guy)
model3D:SetActive(true)

game:GetService("RunService").RenderStepped:connect(function ()
    local fullRotation = math.pi*2
    local currentRotation = tick()%fullRotation
    model3D:SetCFrame(CFrame.Angles(0,currentRotation,0))
end)