How do I get my theme to a staging area without activating yet?

I have the new theme downloaded (Evolution Pro) and can view my site in the "live preview" area, but don't want to go live/ activate/publish it until it's ready. I have tweaking to do first- change of themes was not seamless. I am not a tech person. So, I need simple instructions to create a staging area to work on it until ready. I am @ BlueHost. I know there is a way to name it "test"(name).(url) or something like that, but don't know how to do it step by step. The tech people @ BlueHost are not WP trained unless you pay for one. Thanks!