Incrementing the displayed number of rows in a table



I am using LiveCycle 9.0 and I have made a dynamic table with a button that I have actioned to add a new row. I would like each row to have a number that increments each time the button is clicked to add a new table row on the dynamic pdf. What script do I need to make those numbers appear? I curently have the first cell of the table as a text object and do I select "initialize" "Calculate" what from the script menu?

Please help.