This is my first time experiencing with gui tweens, why does this not work?

Hello wowie, my name is Swift. I am here to help you:

I have expected errors: 1: There are 5 arguments in UDim2.new() 2: I recommended using only one :WaitForChild() 3: I recommended not to shortcut 0.1 4: If the GUI was already in the player's screen, with that configuration, the GUI will disappear almost immediately, if you want it to go out from the user's screen; please use 'In'; but from my consideration; the GUI must be some sort of bar; so you can use out. You might want to fix "0.1" speed though, it's too fast.'

This might be the fixed version.

local SBar = script.Parent.BackG:WaitForChild("Sbar")

while _G.Stamina > 0 and wait(0.1) do
    print("test")
    SBar:TweenSize(UDim2.new(0,_G.Stamina/100,0,1),'Out','Quint', 0.1, true)
end