Hi,

1/ If you can't edit that page - that mean you've installed that plugins or you don't use administrator account.

2/ This issue caused by you didn't select a menu for your topbar menu.

Please go to Appearance > Menus > create a new menu for Topbar menu at the top left > scroll down and check to "Topbar Menu"

For more information about how to config homepage magazine, please check on this video tutorial.

Best Regards,

PenciDesign