What Script Do I Need For A Loading Bar? Start GUI

I Need A Script That Says Like Loading All The Way To 100% To Prevent Any Lagging, And Then I Will Add It To The Start GUI

percent = 0

for i = 1, 100 do
	script.Parent.Size = UDim2.new(script.Parent.Size.X.Scale + .01, 0, 1, 0)
	percent = percent + 1
	script.Parent.PercentDone.Text = percent.."%"
end
	

Thats just a quick example on how it could be done. Its not 100% fancy because I'm not going to write a script that creates the GUI because thats a pain.