How to display categories at top of page

Please can you advise how I can display the list of category sub-sections to the top of a page, like here: plugin - Discourse Meta

Thank you in advance,

In your category settings:


Thanks so much. And how do I change the order of those new boxes please?

First you should check that this site setting fixed category positions is flagged.
Then you can re-order categories and subcategories from the category page (if you have many of categories to fix).

Otherwise you can change position for each category/subcategory from their settings