Click change-column properties-select > final list column or channel cover.

Ok, then you can add child columns.

Supplementary explanation about column attributes:

In the final list column, the list template is used by default, and the content is displayed as a paginated list.

By default, the channel cover uses the channel cover template. The content is generally limited to multi-column aggregation, similar to the home page, but only the home page of the channel, and also used to make a single page about us, contact us.

External link, jump to "file storage directory" to fill in the link, this column does not use any template, and the presentation form is subject to the actual link target, and the link will go wherever it goes.