This article is related to PromoteMyPlace Version 2 only. Not sure which version of the application you're using? See Which version of PromoteMyPlace am I using?
To view the website as it is before any changes have been published, choose ‘View Website - View Live Site’ from the main menu
This will show you your live website within the site builder.
Note that there will be a menu at the top of the screen to get back to the site builder or edit the page, you're on but website visitors won't see this when viewing your website.