RANKX over 2 columns

You can do this in Power Query with a few steps. Can also be done in DAX, but went with the Power Query version first.

Steps:

1. Group the table by Group, and want All Rows as the aggregation
2. 
3. Add a custom column to sort each sub-table by Sales high to low with this code:

Table.Sort( 
[All Data], {"Qty Sales", Order.Descending})

• Then add another column with will but an idex (or rank in this case) to each subtable starting at one and incrementing from there. This is why we needed to sort in the previous step:

Table.AddIndexColumn(
[SortSubTable], "Rank", 1,1)

• Remove all the other columns except the one just created
• Expand that column
• Set data types and sort if you want

Final Table:

But now looking at your request, that may not be what you had in mind!  If you want to rank over the entire table this will work:

Rank = RANKX( ALL( BasicTable), [Total Qty],,DESC,Dense)

Hopefully some of that was helpful :)

gluizqueiroz  add following column in your model and this will do

Rank = RANKX(  ALL( Table5 ) ,
    Table5[Qty Sales], , DESC, Dense )

here is the output

gluizqueiroz 

As a MEASURE, we could use

Ranking =
RANKX (
    ALLSELECTED ( Fact_Sales[Product] ),
    CALCULATE ( SUM ( Fact_Sales[Qty Sales] ), ALL ( Fact_Sales[Group] ) ),
    CALCULATE ( SUM ( Fact_Sales[Qty Sales] ) )
)