The first thing you will need to do is make the page where he registers. Basically, you need to store his name and password somewhere. You could also store his links now, or you can let him add them later.
So, make a page called register.php. In this page, make an html form with at least two inputs and a button. Make this form submit to itself, and check to see if it gets any inputs, and if it does, store them.
How you store them is up to you, basically either a file or database, with database being the right way to do it.