In your control panel, it is possible to keep an entire site from being indexed by search engines. This is done from Website > [name of site] > Site settings. You then uncheck the box next to "Allow search engines" and click the button "Save site." 

To exclude a single page from being indexed by search engines, you can add a meta tag to the page template. Place the following code at the top of your page template:

<meta name="robots" content="noindex">

Then click the "Save and publish" button. More information on using meta tags to block access to your site is available from Google.