If you want to view a different page there are a few ways to do that, the first could be opening the page in the editor and then previewing the page you are looking at.
Or if you want to access everything from the preview mode you can make a link or button that goes to the page you want. You can do something like a menu or links on the top of the page, or however else you want to design it.
Does that help? If you need some more help let me know. I am making small video tutorials each day to help bubblers out.