Displaying DISTINCT Values on Table

[ramsqlik]

With Refrence to my previous post

https://community.qlik.com/t5/QlikView-App-Dev/Calculation-of-Total-Tax-per-Bill/td-p/1819964 

Since above posting is closed. I am opening another posting. My applogies. 

My data looks like below.

Point to note, if an invoice has multiple items, then every item one row is generated.

Dimensions

Bill Date

Bill Number

Vendor Name

Expressions

Sum(IGST)
Sum(CGST)
Sum(SGST)
Sum(Item Total)
Sum( DISTINCT  SubTotal)
Sum(DISTINCT Total Amount)

I want to sum all the data for every invoice and create one line  per invoice. How do I get distnct Invoice_Number?