
Explanation:

Box 1: Top N
Scenario: The Top Customers report will show the top 20 customers based on the highest sales amounts in a selected order month or quarter, product category, and sales region.
Once you drag to SKU to Visual level filter you should get Top N option Note: The two most common filter types: automatic and manual.
Then there are more advanced filters.
Box 2: Visual
Once you drag to SKU to Visual level filter you should get Top N option.
Reference:
https://powerbidocs.com/2020/01/21/power-bi-top-n-filters/