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?
You can watch the following video or read the article below it.
From the ‘Website’ dashboard, choose ‘Pages’
Find the page you wish to edit and select ‘Actions’, then ‘Edit’
Select ‘Open Page Builder’
Make the changes you want and publish them to your live site when ready.