Dummies Guide to creating a staging/test site?

I have looked everywhere for an EASY way to redesign my website without taking it down and I’m hoping there is someone out there kind enough, patient enough to walk me through how someone who is NOT a developer can do this. I seem to remember this is called having a “staging” or test site that you then roll out live when you’re ready.

So it’s a Dummies Guide to Creating a Staging/Test Site I’m on a quest for: any brave persons who can help?

There are many posts asking about this, and all the answers I’ve seen make no sense to me because I’m one of those WordPress users who hates to touch FTP never mind this mysterious thing called PHP. I have no idea what my database is called either. I install WP using Dreamhost’s One-Click installs and then I just use the WP admin tool and that’s it. So all this talk of changing your config file is Greek to me.

I saw a plugin called Dev and Staging Environment but I gave up because it was asking for settings that I don’t know how to answer. Everything else is so easy in WordPress — why is this so hard?

Thanks in advance for any help! I bet there are a lot of other people who’d love to know how to do this too.