Custom URL points to United States version of site and not default

Hi,

Custom URL landing page is set to United States currently. How do I set it to Default from the dropdown menu at the top of the theme editor? Has to be some kind of setting I’m missing?

Dropdown menu on Theme editor: Default, International, United States. How do I make sure the homepage is consistent on each? Right now, Default and International look one way and United States looks another.

Thanks!