For export of data generally the option in File > Export is used. However, for a Chart with multiple data series from mixed locations or sources this often might not be the best approach, as with the standard export all selected Variables are exported on all selected Locations. For a Chart there is a specific Export button directly in the chart definition view “Details of Chart 1” etc., next to the “Apply” button. Use this Export to get all data series in the current chart exported to a single csv-file.