Top 10 and Bottom 10 values by Sales

1) First you create a set for top 10 Products by Right click on a product field-> then create a set -> then select "Top" ->  then define "10", choose "Sales"  with sum.

2) Create second set  for create Bottom 10 Products by right click on a product field -> create a set -> then select bottom -> then define 10, choose sales with sum

3)  now combine the first and second set, by clicking on any one of the sets and -> selecct combine set -> select all values 

4) First drag the sales in to rows shelf, and then Products in to columns shelf.

5) Now drag the combine set in to the filter shelf... now your view will have only top 10 and bottom 10 values by sales.