How to make a popup that appears when you join a game?

This is not a request site lol.

1.) Make a screen gui. Put it in starter guis.

2.) Add a frame into the screen gui. Change the size of the frame to be {1,0}, {1,0}. And then change background transparency to 1. And set he position to {0, 0},{-1, 0} https://imgur.com/a/2nzMItq https://imgur.com/a/UbXYyNE

3.) Add a text label into the frame. Change the size of the label to be {0, 500},{0, 300}. Also set the position of the frame to be {0.5, -250},{0.5, -150}. And set the background transparency to 1. https://imgur.com/a/KiJeiJ6 https://imgur.com/a/UbXYyNE

4.) Make a remote event and put it in replicated storage. Rename the remote event to 'ShowThatDecal'.

5.) Make a script put the below in it:

SCRIPT: (Put in Server Script Service)

game.Players.PlayerAdded:Connect(function()
    wait(1)
    game.ReplicatedStorage.TeleportFullEvent:FireClient()
end)

LOCAL SCRIPT: (Put in the Screen Gui)

game.ReplicatedStorage.ShowThatDecal.OnClientEvent:Connect(function()
    wait(5)
    script.Parent.Frame:TweenPosition(UDim2.new(0,0,0,0), 'Out', 'Linear', 0.5)
    wait(2) --/How long you want it to be on screen (it HAS to be at least 0.5)
    script.Parent.Frame:TweenPosition(UDim2.new(0,0,-1,0), 'Out', 'Linear', 0.5)
end)

This is the best I can do for you. This DOES works for me. Here are some helpful links for this. https://developer.roblox.com/api-reference/function/GuiObject/TweenPosition

https://www.youtube.com/watch?time_continue=53&v=VVQzx6yamJU

https://developer.roblox.com/api-reference/event/Players/PlayerAdded

https://developer.roblox.com/api-reference/event/Player/CharacterAdded

You have to do a game.Players.PlayerAdded function, then copy or make a screengui then a ImageLabel and a button to disable the screengui so it's gone in the player's perspective.

I have something similar which is a loading screen. I'll post a link to the model I made. You can change out the loading screen part and replace it with your decal. It'll cancel the main Roblox loading screen that has the thumbnail on it. Then it will instantly spawn in a loading screen decal. The main script that in placed in "Replicated First" toggled the default loading screen, toggles the top bar, and clones the loading screen into StarterGui. It will stay on the screen for 10 seconds until the game is fully loaded. It will then lower down and be destroyed.

Here's the link for the model: https://www.roblox.com/catalog/03204984196/redirect Sorry that I can't manually explain it all, it should be easy if you know what the things mean in the script.