What's wrong that makes this code not work?

I have the following code that does not do what I want. I want to make it so that for every player, an announcement shows up letter by letter, just like Daxter33's Paintball! announcements. I tried this but wont work, no errors too.. Could someone help me please?

Players = game.Players:GetChildren()
function Deathmatch()
	wait(2)
	Time = 5
	for i = 1,#Players do
		String = "Round Chosen: Deathmatch"
		for b = 1,#String do
		Players[i].Backpack.GameHint.TextLabel.Text = Players[i].Backpack.GameHint.TextLabel.Text..String:sub(b)
		wait(.2)
		end
	end
end
game.Players.PlayerAdded:connect(Deathmatch)

Recheck your code, and you'll find a few mistakes; You are using the 'GetChildren' method, but you may be wondering, 'what is wrong with that?', well, if there was a 'Hat' type instance in 'Players', GetChildren will count the hat aswell, let's try using the 'GetPlayers' instead. :)

local Players = game.Players:GetPlayers() --The 'GetPlayers' method gets all current 'Player' type instances that is in 'Players', so if there were to be a 'Hat' instance, it would return as 'nil'

function Deathmatch()
wait(2)
local Time = 5 --What is 'Time' used for?
for i,v in pairs(Players) do --Ya, I switch out your old 'for' loops with a more efficient one :)
if v then --Check if 'Player' is existant
String = "Round Chosen: Deathmatch"
for i2,v2 in pairs(String) do
if v:FindFirstChild("PlayerGui") and v.PlayerGui:FindFirstChild("GameHint") and v.PlayerGui.GameHint:FindFirstChild("TextLabel") then --Checks to see if 'PlayerGui', 'GameHint', and 'TextLabel' are existant within 'Player'
v.PlayerGui.GameHint.TextLabel.Text = v2:sub(1,i) --Ah, now doesn't this look much better? :)
end
wait(1/19)
end
end
end
end

game.Players.PlayerAdded:connect(Deathmatch) --Connects the function 'Deathmatch' to the event; fires when a Player joins
for i,v in pairs(Players) do Deathmatch() end --The 'PlayerAdded' event does not work in Studio mode, so you use this :)

Also, GUIs do not show up in the 'Backpack', they show up only in the Player's 'PlayerGui', 'SurfaceGui', or 'BillboardGui', which is why I switch your code from Backpack to PlayerGui. Hope this helped!

Alright, I will fix your code up for you just to make it work, good luck!

local Players = game:GetService("Players"):GetPlayers()
function Deathmatch()
	wait(2)
	Time = 5
	for _,Player in pairs(Players) do
		local String = "Round Chosen: Deathmatch"
		for i = 1,#String do
			Player.Backpack.GameHint.TextLabel.Text = tostring(String:sub(1, i))
			wait(0.2)
		end
	end
end
game:GetService("Players").PlayerAdded:connect(Deathmatch)