I am making wordpress template. I've made mega menu on it. Such as on screenshot. But it is only in html. How to add custom settings in wordpress console for users, to add menu items etc.. ?
The wordpress function to create menus is wp_nav_menu however I'm not sure it will work with your menu, it will depend of the structure you developed your mega menu and if it's like the default output by the wp_nav_menu function.
If it's not you will need to write a menu nav walker function.
You can check more about that here
Maybe if you can shere your mega menu code I could help you more.