Okay, thanks, the custom CSS worked.
@mdshak, the screenshot I sent was from my web browser. I’m not sure why there is a difference between mine and yours.
I don’t know how to include screenshots, so I just made a new page and included screenshots. Go to: http://heffernlab.com/screenshot/. Currently the menu is represented by an icon that has horizontal lines (first screenshot), and to see the menu I need to click on this to show the menu items (second screenshot). Based on the picture here: https://wordpress.org/themes/oria/ the theme shows the navigation menu as horizontal, with each menu item being listed. How can I have my menu look like that instead of what it currently is?