If you are just starting out and you goal is to make your own webpage, the best way to do it is not to. Especially login and registration scripts. Due to security holes, I would not suggest that the first script you write is a login/registration script. Even long-time coders leave security holes.
Instead, use someone else's script. Modify it. Tinker with it. Learn from it. I learned most of my ASP from examples in WWF code or in looking up things on the internet.
On one of my major websites, I used WWF as the base login/registration system for the entire website. I then wrote my own code that interacted with that. Over time I was able to build more and more things myself without using other people's scripts. And I don't have to worry about security issues with the login script since WWF maintains that code, not me.
Of course, part of what I said depends on what your goals are. If you are trying to learn ASP so you can put up your own website, then use someone else's login/registration script until you have enough experience behind your belt to write a secure one. If you are just trying to learn and don't plan on using your code in a production environment (like if you are a student who's instructor will check your code), then go ahead and write your own login/registration script. Your instructor hopefully will be able to check it to see if its secure or not.