How to make first person arms script that can go up or down?

Hi, Im trying to insert in my first person arms script, and i don't know how to make it so it can go up or down, as im having a issue with this.

--// made by joshuasol\\--
--//Variables\\--
local Player = game.Players.LocalPlayer
local Character = Player.Character or Player.CharacterAdded:wait()
local Humanoid = Character:WaitForChild("Humanoid")
--//Cloned Arms\\--
local Arms = Instance.new("Model", workspace)
local NewHumanoid = Instance.new("Humanoid", Arms)
local Shirt = Instance.new("Shirt", Arms)
local Head = Instance.new("Part", Arms)
Head.Size = Vector3.new(0.05, 0.05, 0.05)
Head.Name = "Head"
Head.Anchored = true
Head.Transparency = 1
Head.CanCollide = false
NewHumanoid.RigType = Humanoid.RigType
Shirt.ShirtTemplate = Character:WaitForChild("Shirt").ShirtTemplate
Arms.Name = " "
--//End of Cloned arms\\--
local ArmNames = {"LeftHand",
                  "RightHand",
                  "LeftUpperArm",
                  "RightUpperArm",
                  "RightLowerArm",
                  "LeftLowerArm",
                  "Left Arm",
                  "Right Arm"}

--//Functions\\--
local function Show(Part)
    for i, ArmName in pairs(ArmNames) do
        if Part.Name == ArmName then
            local Clone = Part:Clone()
            Clone:ClearAllChildren()
            local Weld = Instance.new("Weld")
            Weld.Part0 = Part
            Weld.Part1 = Clone
            local CJ = CFrame.new(Part.Position)
            local C0 = Part.CFrame:inverse()*CJ
            local C1 = Clone.CFrame:inverse()*CJ
            Weld.C0 = C0
            Weld.C1 = C1
            Weld.Parent = Part
            Clone.Parent = Arms
            Clone.CanCollide = true
            Part.Transparency = 1
            if Humanoid.RigType == Enum.HumanoidRigType.R6 then
                for i, Object in pairs(Character:GetChildren()) do
                    if Object.className == "CharacterMesh" then
                        if Object.BodyPart == Enum.BodyPart.LeftArm or
                           Object.BodyPart == Enum.BodyPart.RightArm then
                        --
                        local ClonedMesh = Object:Clone()
                        ClonedMesh.Parent = Arms
                        --
                        end
                    end
                end
            end
        end
    end
end

local function Loop()
    for i, Object in pairs(Character:GetChildren()) do
        Show(Object)
    end
end

--//Events\\--
Humanoid.Died:connect(function()
    Arms:Destroy()
    Player.CharacterAdded:wait()
    Loop()
end)

Loop()