Why is my Group Hint Gui script erroring?

For some reason, it isn't working, I've tried doing some changes, but it just comes up with the same error, the error says 15:08:57.372 - Players.Player1.PlayerGui.ScreenGui.LocalScript:7: bad argument #1 to 'sub' (string expected, got table) 15:08:57.373 - Script 'Players.Player1.PlayerGui.ScreenGui.LocalScript', Line 7 15:08:57.374 - Stack End, but I don't get what I'm doing wrong, here is the script;

repeat wait(0)until game.Players.LocalPlayer and script.Parent and script.Parent.Parent and script.Parent:FindFirstChild("GroupText",true)

local Texts = {"Hello, and welcome to TheeDeathCaster's HOLO Facility!","If there are no Trainers around, then please wait or request a High Rank.","If you are a High Rank and you want to host a Training, then please notify TheeDeathCaster before doing so.","Be user friends to your comrades, or else that will result in you getting kicked and banned from the group.","If you have any questions please let TheeDeathCaster know."}

while game.Players.LocalPlayer:IsA("Player") do
for z = 1, #Texts do
script.Parent.GroupText.Text = tostring(string.sub(Texts,1,z))
wait(.7)
end
wait(3)
end