Changing the Permalink on my editing/work page

My web hoster assigned me a sub domain so that I could build my new web page and learn the new software without interfering with my present web site. The problem is the permalink at the top of my provisional home page is showing my PRESENT, active web site. I don’t want to go there until I’m ready. How do I change the premalink url address to point to the provisional sub domain and not my active domain?
Many thanks.
Ted Vigodsky