TweenLib example

--Initialize tween:
TweenLib.newCFrameTween("test",--Tween name
    CFrame.new(),--Initial value
    function(cf) part.CFrame=cf end,--An optional function to update the items related to the tween, it's only purpose is to to be called by TweenLib.updateCFrameTweens
    1--A number or function that specifies how long the tween should take, defaults to 1 if nothing is given.
)

--Tween to a CFrame:
TweenLib.CFrameTween.test=CFrame.Angles(1,2,3)

--Animate the tween(s) in the main loop:
while true do
    TweenLib.updateCFrameTweens(tick())--call the 'update function' used in the initialization
    wait()
end

--Alternatively, you can obtain a freshly calculated value every time you index the table:
part.CFrame=TweenLib.CFrameTween.test