How to attach billboard Gui to shirt?

I got this billboard gui and i wanna attach it to my shirt any ideas?

local X = 324 local Y = 157 local P = Instance.new('Part')
P.Name = 'Bitmap'
P.Anchored = true
P.Transparency = 1
P.Position = Vector3.new(0, 0, 0)
P.Parent = game.Workspace

local B = Instance.new('BillboardGui')
B.Name = 'Image'
B.AlwaysOnTop = true
B.Size = UDim2.new(0, X, 0, Y)
B.Parent = P
local F = Instance.new('Frame')
F.Name = 'Holder'
F.Size = UDim2.new(1, 0, 1, 0)
F.BackgroundTransparency = 1
F.Parent = B
local res = 2 local current = 1

local cooldown = false

local cooldowncount = 0

for _,v in pairs(imageBytes) do
    local frame = Instance.new('Frame')
    frame.BackgroundColor3 = Color3.new(v.r/255, v.g/255, v.b/255)
    frame.Size = UDim2.new(0, 1, 0, 1)
    frame.BorderSizePixel = 0
    frame.Position = UDim2.new(0, math.floor(v.x/res), 0, math.floor(v.y/res))
    frame.Parent = F
    if frame.BackgroundColor3 == Color3.new(0, 0, 0) then
        frame:Destroy()
    end
    current = current+1
    if current % 2 == 0 and not cooldown then
        cooldown = true
        wait()
    elseif current % 2 == 0 and cooldown then
        cooldowncount = cooldowncount+1
        if cooldowncount == 25 then
            cooldowncount = 0
            cooldown = false
        end
    end
end