How do I tween multiple parts?

So I have model that I'm trying to tween but I can't seem to get it working. I tried looping through the model and doing local example = game.Workspace.example.PrimaryPart but that didn't work either. I'm at a lost for what to do right now so help is appreciated.

local on = false

local TweenService = game:GetService("TweenService")
local TweeningInformation = TweenInfo.new(
	8,
	Enum.EasingStyle.Bounce,
	Enum.EasingDirection.Out,
	0,
	false,
	0
)

local goUp = {CFrame = CFrame.new(-217.408, 2.934, 12.847)}
local goDown = {CFrame = CFrame.new(-217.408, -31.094, 12.847)}

script.Parent.ClickDetector.MouseClick:Connect(function()
	if on == false then
		for _,v in pairs(game.Workspace.Present:GetChildren()()) do
			local tweenUp = TweenService:Create(v,TweeningInformation,goUp)
			tweenUp:Play()
		end
		on = true
	else
			for _,v in pairs(game.Workspace.Present:GetChildren()) do
				local tweenDown = TweenService:Create(v,TweeningInformation,goDown)
				tweenDown:Play()
			end
			on = false
	end
end)