You need to do two things: 1) place the robots.txt file with the denying code at the root of the site, 2) add the noindex meta tag.
There are other methods, but they are complex and don't make much sense when applying the first two.
1) the noindex meta tag looks like this
<meta name="robots" content="noindex">
and is placed in the code structure between <head> and </head>
2) the robots.txt file looks like this:
User-agent: *
Disallow: /
just copy and paste this into notepad and name it robots.txt. Download it at: your-site.com/robots.txt