Description and FY has to be created using calculated field.
Unfortunately calculated fields does not allow to give calculation like if [measure name] = "Quantity" then "Desc for Quantity"
https://community.tableau.com/thread/141643 refer this which addresses the same issue
Here is one helpful way to do this when users hover over the fields. You could also alias the fields
There are a few other work arounds but this would be the fastest solution. Let us know if you need additional assistance.