My script seems to be working but it is not running correctly, could anyone help?

I have written code so that two separate GUI from other sides to come in like cinema curtains, then go out. I put one script in the SCREENGUI next to the Frames, (the curtains). When I play only one side functions. Could anybody explain why and write the alternative answer to this? I put the code in a LocalScript.

local TransitionScreen1 = script.Parent.TransitionScreen1
local TransitionScreen2 = script.Parent.TransitionScreen2

function Transition1()
    TransitionScreen1:TweenPosition(UDim2.new(-0.5,0,0,0), Enum.EasingDirection.In, Enum.EasingStyle.Sine, 2, false, nil)
    wait(3)
    TransitionScreen1:TweenPosition(UDim2.new(-1, 0, 0, 0), Enum.EasingDirection.Out, Enum.EasingStyle.Sine, 2, false, nil)
    wait(3)
    TransitionScreen1.Position = UDim2.new(-1,0,0,0)
end


function Transition2()
    TransitionScreen2:TweenPosition(UDim2.new(0.5,0,0,0), Enum.EasingDirection.In, Enum.EasingStyle.Sine, 2, false, nil)
    wait(3)
    TransitionScreen2:TweenPosition(UDim2.new(1, 0, 0, 0), Enum.EasingDirection.Out, Enum.EasingStyle.Sine, 2, false, nil)
    wait(3)
    TransitionScreen2.Position = UDim2.new(1,0,0,0)
end


wait(2)
print("test")
Transition1()
Transition2()