Sum function not summing across rows

Hi, Knack newbie here. I have an Order Sum field where it is not displaying the Total Order Amount but the individual Line Item Totals in a single cell (screenshot below, Total Order Amount should be $50). I’m probably overlooking something basic here where it’s summing horizontally across my Line Item columns but not vertically across rows. Appreciate any quick pointers.
Order amount

Is this what you want?

See this video

Hi Peter, yes that’s right I want to show the total sum across all the line items

My issue was i was trying to sum at the child table level and had to sum at the parent table level to sum across rows. resolved!