How do I change the GUI for everyone in a server if it's in StarterGUI?

I'm trying to add a timer script where when I type a message, a timer starts ticking down on everyone's GUI. The trouble I am having is accessing everyone's GUI's at the same time to change them all at the same time. The script is currently in ServerScriptService and the GUI itself is in StarterGUI. I guess you could say that this kind of GUI is like a server-wide message that I control when it starts.

--This is an attempt of me doing it.
local p = "elian11";

local t = game.Players:GetChildren();
local timer = t.PlayerGui.Timer.Frame.TextLabel

game.Players.ChildAdded:connect(function (newPlayer)
if (newPlayer.Name ~= p) then return; end
newPlayer.Chatted:connect(function (msg)
msg = msg:lower();
if (msg == "raid/timerstart") then
timer.Text = "This script works"
--You can ignore this part, I will add it once it starts working.

end
end);
end);

http://wiki.roblox.com/index.php?title=API:Class/Instance/GetChildren

you are missing for i,v in pairs () do

use the link above to fix your script.

Hi! I see your problem, and the best solution to your problem is to use an in pairs loop. Basically, I have fixed up your script and this is the fixed version:

local p = "elian11";

local t = game.Players:GetChildren();
local timer = t.PlayerGui.Timer.Frame.TextLabel

game.Players.ChildAdded:connect(function (newPlayer)
if (newPlayer.Name ~= p) then return; end
newPlayer.Chatted:connect(function (msg)
msg = msg:lower();
if (msg == "raid/timerstart") then
for i,v in pairs(t) do
v.PlayerGui.Timer.Frame.TextLabel.Text = "This script works."
end
end
end);
end);

What I did was I used an in pairs loop to loop through all the players, and if the player has the gui then it will change the timer's textlabel' for every player.