Upon creating a new page, or if you need to change any content in your pages, you will have to edit your page. On this article are a couple of things you need to know.
At the top right are two buttons, "Edit" and "Preview".
By default, every page in Publisher is displayed in "Edit" mode, where you can change the text and images in all editable fields. All text is kept to the simplest style for editing purposes, so you don't see headers and sub-headers in their correct sizing.
By clicking on the "Preview" button, the styles and spacings of the page are applied, so you get a preview of how the page would look on the live site.
You can click between "Edit" and "Preview" mode as often as you like. It does not affect the page, nor save any changes. When you leave the page, you must click on "Save" or "Save & Approve", otherwise you will lose any changes you've made.