To create a new Page with a dropdown menu:
- Go to Webmaster.
- Scroll down to last page displayed and click Add New Page (not the blue Add News button).
- Select the type of page and the preferred navigation.
- For the option to add a sub menu, choose Add new nav menu and make page a sub.
If you have already created the Page, you can select the small Edit this page title pencil underneath the Page name on the display of Pages in Webmaster.