If you need to test new themes, plugins, or just about anything but you don’t want your entire site be compromised, what you can do is move your Live WordPress to your local server. In this way, you’ll get to test just about anything without worrying that it might destroy your site. Also, it is a great way to practice your WordPress coding skills as you are dealing with a live WordPress data, not just a dummy site.
First you need to install a plugin that duplicates a page or your entire site. The Duplicator is the best plugin for that.
Then create a backup of your entire site. Just in case.
After that, follow these steps: http://www.wpbeginner.com/wp-tutorials/how-to-move-live-wordpress-site-to-local-server/