With the two icons 
Series in columns and 
Series in rows on the contextual ribbon tab Chart | group Data, you can determine whether the data to be displayed is to be evaluated column by column or row by row:
▪By columns
| By default, the first icon is selected, meaning that the data is evaluated column by column. The values in the first column will be the first data series, the values in the second column will be the second data series, etc. |
▪By rows
| If you click the second icon, the data will be evaluated row by row. The values in the first row will be the first data series, the values in the second row will be the second data series, etc. |
Alternatively, you can also find this setting in the dialog box of the ribbon tab Chart | group Data (click on the group arrow
) and switch to the Data source tab.