the best method would be to set up a Staging site, your host should be able to help with this. Then you can spend as long as you like configuring the staging copy of your site and when you’re happy the host will push those changes to the live site.
I haven’t had any experience with that plugin so cannot recommend. Quickly reading the reviews it seems you require the Premium version to use it correctly. I would be cautious and make sure your host has a backup before proceeding.