[Eikinskjaldi]

How to make a plugin instructions can be found on this board. Do a bit of searching. Really, you just did the equivalent of logging onto a php site and asking "how do I code in php?"

Here is a couple of pointers...

If you import global.php into your script you have access to the $vbulletin object, including the $vbulletin->db object which is already connected to your database and comes with a bunch of helper functions

vbulletin uses a template system, which means it separates php and html. It is rare you concatenate some html and print it, much more likely you eval template.

Do some research, ask a specific question.