You can find all of your pages in the Manage Pages section of your Dashboard. To switch templates easily click on the Templates Button up the top left of your Dashboard. When you do this on your 30-day free Website trial you can have the option of inserting the 6 or so pages of example content layouts from that template automatically — so that it gives you a head start in building your pages.
If you have edited the content or design of any of the pages before changing templates, those pages will still be available in your Manage Pages area of your dashboard after changing templates, but they will just be moved out of your main navigation menu.
After you've logged into your website, on the left-hand side, click on "Manage Pages".
All the pages that you've created or have edited are now listed below the PAGES ABOVE THIS LINE APPEAR IN THE MENU line. You can find out more about changing what pages appear in the menu by reading this guide.
All pages that were inserted from a previous template and not edited get deleted to help keep things tidy when you switch templates. However, if you are wanting to use one of those pages, you can restore them from the deleted pages section - just click Bring it back on the page you want to restore.