Run the time gui after a mode is chosen?

My problem is, I have a CountDown Gui at StartGui i want to do is when a mode is choosen the gui will start counting.. Here's the CountdownGui Script.

local time = 15 --Change this to how many seconds till zero. 
for i = 1, 15 do --Change the number to the one you have above. 
wait(1) --Do not change.
time = time - 1 -- Seconds decreased each second. 
script.Parent.Text = tostring(time) 
end -- DO NOT DELETE
script.Parent.Text = "Owch"
script.Parent.Parent.Parent.Parent.Character.Humanoid.Health = 0 -- Remove script if you do not want to die at 0

And this one is the mode choosing script

while true do --This makes sure it keeps going and doesn't die out on us
wait(5) --This is how long until the games are started. Recomended that you keep to 5
local m = math.random(1,1) --This randomly selects a game. The seven shows how many games there are
local player = game.Players:GetPlayers()
for i = 1, #player do --This checks for players and gets them
msg = Instance.new("Message") --This make the annoying messages that appear on you screen
msg.Parent = nil --This identifies the game
if m == 1 then --don't change unless you know what you are doing
msg.Parent = game.Workspace --This makes sure it says and appears in the workspace
msg.Text = "Choosing Obtical." --A bunch of messages to tell you that the game is starting which you can change if desired
wait(1)
msg.Text = "Choosing Obtical.."
wait(1)
msg.Text = "Choosing Obtical..."
wait(1)
msg.Text = "A Obstical has been chosen!"
wait(3)
msg.Text = "The Obstical is..."
wait(3)
msg.Text = "Acid Leap!" --Put the name of the minigame you want it to be called
wait(2)
msg.Text = "Hop to the end without touching the acid or you will tele to the begining!" --Put the rules of the minigame
wait(5)
msg.Text = "The game will be starting in:"
wait(1)
msg.Text = "...3..."
wait(1)
msg.Text = "..2.."
wait(1)
msg.Text = ".1."
wait(1)
msg.Text = "Begin!"
wait(1)
player[i].Character:MoveTo(Vector3.new(-37,4.2, -479)) --Replace 206, 31.4, 48.5 with the location of where you want all players to be teleported to at the start of the minigame
msg:remove() --This removes the annoying messages Don't mess with!
game.Lighting.Minigame1:clone().Parent = game.Workspace -- Make a minigame then name it just like this: Minigame1 Once it is named that, put it in the position on the map were you want it to go then put the model in lighting. After you put the model in lighting, you may delete the one in workspace if you wish.
wait(10) --How long the game lasts

[Here i will put the script for the countdown gui to run?]

Thanks for helping!!