Creating a test site

I am trying to set up a test site using a subdomain.
My main site is https://www.xbydesign.biz and the test site is set up as the subdomain testsite.xbydesign.biz.

I created the subdomain via Bluehost, my hosting provider, and then copied everything into it’s folder from the main site. (I created another subdomain in this same manner and it works fine.)

I can see the test site (and can tell that it’s test by some small details), however I am unable to edit it. It seems there is no admin panel for it because if I edit what I *think* is the test site, my live site changes.

Please let me know what other info I can provide to help facilitate resolution. Any help is appreciated.
Thanks.