How do i script --> countdown then teleport?

please tell me how to script after countdown then everyone get teleport D:

In this script we're going to use the wait function, a for loop, and TeleportService:Teleport().

local timeUntilTeleport	= 30		-- time in seconds
local placeId			= 1234567	-- destination placeId

wait(timeUntilTeleport)
for _,plr in next, game.Players:GetPlayers() do
	game:GetService("TeleportService"):Teleport(placeId, plr)
end

This code would wait 30 seconds and then teleport everyone in the game to the desired placeId.