Getting back on topic...
Login/Register things require some stuff.
1. Do you have a database up and running?
2. Do you have a server on which you are hosting your sie?
3. Do you know anything about scripting at all?
A login system would require various amounts of PHP, HTML, and MySQL. HTML for the form and surrounding webpage, PHP for checking the username and password and adding them as variables, AND to register the session, and MySQL to connect and read the batabase.