SOLVED: How to make a GUI pop up when the server starts?

Hello I have the basics of Lua scripting but I really need help on how to make a GUI pop up when the server starts. I have tried to attempt it but I cannot find a way to do it because there is no function that I can find to do it. Any help would be appreciated.

EDIT: This is a racing game so the first person to join would choose to join the race or not.