You should know the basics of HTML to create a simple register form where it asks the usual information and through a server-side app (eg. PHP) - inside a php block you can verify the information, print to the user - error/success and register your information which is commonly done on a database.
Steps:
- Create register form to insert the user information.
- Record the information into the database.
I recommend learning a bit of HTML on how to create simple forms, it's simple because HTML isn't considered a programming language and just an markup language which creates the website visual aspect alongside CSS.
Take a look also on php.net references regarding PDO to establish a connection to your database and how to fetch and execute queries.