How do you make a starter/intro gui like strobe and darkness with start button and options and stuff

I've always wonder how to do it and never figured it out. Can someone help?

i know how to but without the play button. go to this link http://web.roblox.com/Intro-GUI-Creator-item?id=142427411 then download the plugin.(you must be in rob lox studio) then enter the world you want it on and click the "create intro gui" and go to the script and enter in the needed formula! (it will tell you what you need to do in the script)