Although Power BI has an built-in Top N
filter feature

It is often useful to be able to show
that value as a measure and what percent of the whole it represents

This guide shows you how to do it

Step by Step

Create a measure to aggregate sales for
the top 5 products

We create a Variable to identify the top
5 products, and a separate variable to aggregate the sales amount

This makes the DAX easier to follow

We have then used this measure on a card
to highlight how much of the total the top X products represent

We added a simple secondary measure
showing what percentage this is

We then created similar for the bottom 20
products

And Finally added these to the chart

We hope you find this useful