I dont know how to do this.
gui:TweenPosition(UDim2.new(x-scale, x-offset, y-scale, y-offset), "Out", "Back", 1)
Replace gui
for the path/variable of your GUI
The Xs and Ys represent the end position of the GUI.
"Out" represents the "easing speed".
"Back" represents the "easing style".
"1" represents how many seconds the transition will take.
This link from the wiki provides additional info.