[Opserty]

Maybe start again, this tutorial is more up to date: [How-To] vBulletin API Basics: Creating Custom Pages & Misc.

You've put your custom PHP code all in the wrong place, it should go after it says:

PHP Code:

// #######################################################################
// ######################## START MAIN SCRIPT ############################
// ####################################################################### 


(What do you mean by "It doesn't show up" ? Have you browsed directly to the threads URL? Does it show up then or do you get an error?)