The Preview screen is the right hand side of your screen. In this section, you can preview all changes that you make to your site before they are published to your public-facing website.
On the left side of your screen is your Editor. This is where you will make all your changes to your website. Any changes you make will automatically appear in the preview screen on the right.
However, none of your changes will be published to your public-facing website until you click the blue Save button at the bottom of the editor.
When there are changes pending on your website, the Cancel and Save buttons will turn red and blue. When there are zero changes pending, the buttons will be grayed-out.
After hitting the Save button, all pending changes will be fully published to your live website.