There are two ways to edit your data. Import and manually entering data.
1) Manual Entry
Click on Edit Data and begin typing your data. Changes to your chart are dynamic. Use controls in the header row to add or remove columns. Click on the Add New Series box to add a new row/data series.
Click on Edit Data from the element control bar. Click the Import Data button and paste using your keyboard command(ctrl+v/cmnd+v) directly in the import data box.
Tick off the desired data options (i.e use first column as value series name), then, click Replace Chart Data or Import into New Series.