Customising Menus. Adding social media menu items - how to stop it adding placeholders for all menus not just soc media?

In the WP basics course, we are adding social media links in the customiser. My template is slightly different to the video.

There are word menus for Home, about us, blog, twitter, instagram and email in the menu list. Below that is a row of social media icons. But there is a placeholder icon for each of the above menu items. Six menu items, six icon placeholders. So that there is an icon placeholder for the home page, About us and Blog.

If I remove social media elements from the menu list, they disappear from the icon row.

What am I doing wrong here please?

Surely Twitter, Instagram and email should just be in the icon row and not listed in the menus. And there should only be three icons, not six.

There's no options to change it, seemingly.

Thanks!