Optimizely is a tool for making changes to your website (visually, or in code) to setup A/B tests - it essentially runs ontop of your page, as it's loading. It is not a tool for creating web pages.
You may want to look at Optimizely's page on the visual editor, here, to see what changes you can make easily (or in code, here). If you're looking to create a different version of your page (for example, a full page redesign), you will want to consider creating this page separately yourself and then using Optimizely's 'redirect to a new page...' feature to point to your new page, here.
I hope that information helps you setup your tests!