Output to be vertically displayed

Hi, currently I am hardcoding the column name to write cell value into. I would like to make it more dynamic. Thus, I would like to get the last column Index of the excel then write the table in(4 rows) each time I run.

My code to get Last Column Index(works):
k.Columns.Count + 1
If(Column_Number<=26,Convert.ToChar(Column_Number + 64),Convert.ToChar(CInt(Int((Column_Number - .001) / 26) + 64)) + Convert.ToChar(If(Column_Number mod 26 = 0,26,Column_Number mod 26) + 64))

This is my output after I run the workflow once.

Expected outcome after I run the workflow again.

How can I do this?

Thank you xoxo