I registered mine subdomain on c panel, but I don't know how to work on it in my site studio. How do I get there to start create? Thanks a lot.
You can upload files to your subdomain website yoursubdomain.yoursite.com to proper directory via ftp. Usually on Linux hosting root directory of subdomain site is a directory 'yoursubdomain' inside public_html directory of your hosting account. Ask your hosting provider these details.