How To make mouse able to move in gui??

I made a Fps script and I Don't Understand Why The Mouse Don't Move it just stays in the middle is it possible to make it move? here is the script

--Made By Dragonbreath12234--
wait(.1)
game:GetService('Players').LocalPlayer.CameraMode = Enum.CameraMode.LockFirstPerson
game:GetService('Players').LocalPlayer.CameraMode = Enum.CameraMode.Classic
game:GetService('Players').LocalPlayer.CameraMode = Enum.CameraMode.LockFirstPerson

inside of the Gui, insert a TextButton if there isn't one already.

inside of the textbutton, look for the property Modal. Turn that on.

Modal allows you to move your mouse freely when the TextButton is visible.