How would you go about affecting everyone's UI? My script only runs for one person?

Hello,

This script is supposed to run for all players in the game, but it only seems to run for the latest person that joined? It's strange, and I'm starting to feel like I may be on the wrong path? The script is supposed to affect everyone's UI. How would you go about fixing my script? Or is there a better approach?

I'm quite new to scripting, so all help and explanations are very much appreciated.

This is a server script in ServerScriptService. When there is only one player in the game, it works fine. Here is my current script:

--// Variables

local RepStorage = game:GetService("ReplicatedStorage")
local Players = game:GetService("Players")

local TextGui = script.NPCtext:Clone()
local ServerText = script.ServerText:Clone()
local PlayerText = script.PlayerText:Clone()
local TextSound = script.TextSound
local Text = ""

--// Game Set-up

Players.PlayerAdded:Connect(function(player)
    TextGui.Parent = player.PlayerGui
    ServerText.Parent = player.PlayerGui
    PlayerText.Parent = player.PlayerGui
end)

TextGui.Frame.Visible = false
ServerText.Frame.Visible = false
PlayerText.Frame.Visible = false

--// Functions

function ServerTextAni()
    local GuiType = ServerText
    local GuiText = Text
    GuiType.Frame.Visible = true
    for i = 1, #GuiText do
        GuiType.Frame.Text.Text = string.sub(GuiText, 1, i)
        TextSound:Play()
        wait(0.05)
    end
    wait(2)
    GuiType.Frame.Text.Text = ""
    GuiType.Frame.Visible = false
end

function TextAni()
    local GuiType = TextGui
    local GuiText = Text
    GuiType.Frame.Visible = true
    for i = 1, #GuiText do
        GuiType.Frame.Frame.Text.Text = string.sub(GuiText, 1, i)
        TextSound:Play()
        wait(0.05)
    end
    wait(2)
    GuiType.Frame.Frame.Text.Text = ""
    GuiType.Frame.Visible = false
end

function PlayerTextAni()
    local p = Players:GetPlayers()
    local selected_value = math.random(1,#p)
    local UserId = p[selected_value].Name
    local GuiType = PlayerText
    local GuiText = Text

    local player = p[selected_value]
    local thumbnailType = Enum.ThumbnailType.HeadShot
    local thumbnailSize = Enum.ThumbnailSize.Size420x420

    local content, isReady = Players:GetUserThumbnailAsync(player.UserId, thumbnailType, thumbnailSize)

    GuiType.Frame.Player.Image = content

    GuiType.Frame.Visible = true
    for i = 1, #GuiText do
        GuiType.Frame.Frame.Text.Text = string.sub(GuiText, 1, i)
        TextSound:Play()
        wait(0.05)
    end
    wait(2)
    GuiType.Frame.Frame.Text.Text = ""
    GuiType.Frame.Visible = false
end

wait(1)
Text = "Players are loading, please wait..."
ServerTextAni()

wait(5)
Text = "Hello everyone, welcome to Clarenval Island!"
TextAni()

Text = "I'm Nathan Eyler, your tour guide for the week!"
TextAni()

Text = "Ugh, finally! It took such a long time!"
PlayerTextAni()

Text = "I'm exhausted!"
PlayerTextAni()

Text = "I can see that all of you are tired, don't worry; the cabins are not far away."
TextAni()

Text = "Come with me, I'll show you the way."
TextAni()

Text = "Follow your tour guide, Nathan. Be on the look-out for useful items!"
ServerTextAni()