Creating part with bullet hole decal/surface gui when you fire gun?

So i want to create a script that will create a transparent part with a decal of a bullet hole on it when you fire a gun. How would you do this? I think you use cframe and mouse hit?

If this doesnt work at LEAST dont give me a Thumbs Down,Becuase I did type all this/I used the top of my mind.

--Bullet Fired

function bulletfired()
script.Parent.Bullet:FindFirstChild("Part") then
script.Parent.Bullet.Transparency=1
script.Parent.Bullet.Decal.Transparency=0
end

script.Parent.Trigger.MouseClicked:connect(bulletfired)

--Trigger Clicked

function fired()
tr = script.Parent.Trigger
gui=Instance.new("BillBoardGui",tr)
gui.Size=(100,100)
image=Instance.new("ImageLabel",gui)
image.Image="IMAGEHERE"
wait(2)
gui:Remove()
end

script.Parent.Trigger.MouseClicked:connect(fired)

Now I only gave PART on the script you must get the rest from someware else.