Hello, @Olhangola,
Actually, it is not the secondary menu the widget uses in the header builder is a secondary menu but the menu is not set to the secondary menu there is only 1 menu on your site which is known as the “Main menu” you can find this in the Appearance >> Menu, now if you want to remove the existing menu and set a new menu there you have to create a new menu in the Appearance >> Menu and then set this menu in the Theme Options >> Header Builder as you can see in this image for a better reference: https://postimg.cc/6yHKfDVf
Regards 8Themes Team.