Menu bar not appearing

Dear team,

Firstly let me take the opportunity to congratulate you on the awesome theme developed by you.

However, I am struggling with the option to enable top menu for the website in customizer. Please see attached screenshot [website no menu] [Customizer] to understand and view the issue.

Could you please suggest what I might be missing out on?

The page I need help with: [log in to see the link]