I tried making a fading GUI, and doesn't work?

for loop = 1, 10 do
game.StarterGui.ScreenGui.Fade2.BackgroundTransparency = loop/10
game:GetService("RunService").Stepped:Wait()
end

Tried that^ didn't work.

You’re trying to change the GUI in StarterGui, that’s why. You need to change it in a player’s PlayerGui for it to work.

Here’s a fixed version (Assuming you’re using a localscript) :

for loop = 1, 10 do
game.Players.LocalPlayer.PlayerGui.ScreenGui.Fade2.BackgroundTransparency = loop/10
game:GetService("RunService").Stepped:Wait()
end

This is for a simple script:

wait(10) -- Use any numbers 
script.Parent.Transparency = 0.5
wait(10) 
script.Parent.Transparency = 1