When you launch SiteBuilder, it will automatically open the same site and pages you were editing when you exited the program. If you don't see the site or pages you want to edit, you can easily open them again.
To open a page in your site:
You can easily open a page in your site by double-clicking its name in the Site Contents pane on the right side of your SiteBuilder screen. Click the + symbol to see the pages in any folder.

Site Contents pane
You can also open a page by clicking the Open Page... button on your toolbar and then using the Open dialog to find your page.

Open the page by double-clicking its name or by highlighting its file name and clicking Open.

Keyboard shortcut: Ctrl+O
Toolbar shortcut: 