Ticking bar ( loading bar that fills up when a clock is finished ticking )?

I need to know like how to make a bar fill up when a clock next to it is ticking like say the clock says 6 minutes and it counts down from that I would need a bar to slowly fill up by exactly 6 minutes.

Since this is not a request site I actually tried it but it didnt really make any sense to me but it is something.

gui = script.Parent
player = game.Players.LocalPlayer
for i = 360,0,-1 do
	
	gui:TweenSize(UDim2.new(i,0,1,0))
	wait(i)
end

Tween for 60*6 seconds.