Hi Priya,
You can use Rank () or Use TopN filtering.
Using Rank()
Create rank for the fields using Rank() -
RANK SALES = RANKX(Orders,Orders[Sales],,DESC)
Now place the fields in table and rank sales .
Now sort the rank field and filter out using Top and enter N value.
Using TopN Filtering.
Create a table with required fields and Drop sales.
Now Under Visual Level Filters, under order-id Select TopN filtering, enter the N value and drop sales field in the box below.
Now you can see top N Sales per order/region/ at the last row.etc.
Hope it helps you.