Need Help duplicating a site for live staging..

I am trying to duplicate my site to a live staging area so I can test out some new designs before going live with it.

I want the entire site to be duplicated, however because there is so much content I can’t use the wordpress admin export / import feature. I’ve never done this before, and was hoping someone could help me out with it.

I also want to be sure Google does index the staging site since it would be a an exact duplicate of my existing site.

Thanks so much!