Hi Carol,
Sorry for the trouble there. I just published an update to the theme that I believe will help you out. If you ever need to access something in the customizer but it isn’t cooperating, every option there exists in another spot as well. All of the theme related items are also in the theme options page, including a few that aren’t in the customizer. Also the widgets, navigation menus and front page settings also have their own spots in the admin just in case you ever are in a jam.
One way to make a coming soon page would be to create a page and assign it as your home page. As long as no navigation menu is assigned to one of the theme’s locations, your visitors won’t be able to go deeper in the site than that.
Another option would be to use a plugin like Coming Soon CC (https://wordpress.org/plugins/cc-coming-soon/). It lets you add in a splash page that visitors who aren’t logged in see, while logged in admins get the actual site that’s under development. When I have to create a coming soon page, that’s how I go about it.
Let me know if you have any questions.
Have a great Saturday,
Bill