How do I add data to an existing graph

I want to add more data to a SS

  • Mark all Data, old and additional ones, and drag them onto the chart.

or

  • Bring chart in edit mode (gray border) and use the Data Ranges dialog (menu Format or icon). Its tab page Data Series has a button Add. For each of the items in field Data ranges: set the values in the field Range for … and if needed in the field Categories.