If the student wants to create "www.bradashley.com" they would need to purchase the domain name from Bluehost, GoDaddy or another domain host site. From there, each one is different but all of them would have a way to upload a HTML file that redirects to your students site on CodeStudio. If the student wants to have each URL be "www.bradashley.com/home, 'www.bradashley.com/cooking, 'www.bradashley.com/hobbies" they'd need to research how to upload their html pages onto the site itself (a while ago you'd do this through FTP, but I'm sure it's easier now).
As for the students posting online - I'd review the Digital Footprint lesson and then have the students read through the "acceptable use policy" for online usage at your school - if you don't have one, have the students create one! There are additional tools out there that will comb through the website to see if has personal information, but having students review each others might be a better exercise.
Let me know if you have any additional questions!