Thanks for asking.
Adding menus in top bar is not possible at the moment. You can do it with custom development but it will fall outside the scope of the support we offer. But I can give you some help to startup.
Your concerned file name is _topbar.php file placed under /framework/legacy/cranium/headers/views/global/ to child theme and put it in the same path inside child theme and modify it. If you would like to know more about how menus works in WordPress, I suggest you to refer following resource:
Would like to also let you know that we also have a Theme that goes by name Pro. Pro gives you the flexibility to easily design the header along with your menu options. We have developed a tool inside Pro known as header builder which make it easy to insert a primary and a secondary menu with just a simple drag and drop of the menu elements. To know more about the header builder, please check this out: https://theme.co/apex/forum/t/pro-header-and-footer-builder-introduction/1033
For more information about Pro theme, please check out Pro section from our knowledge base:
We also have compiled few common questions pertaining to Pro that can be referred here: