Select at least one Y column (or a range from at least one Y column). Ideally, select two Y columns (or a range of two Y columns). If there is an associated X column, X column supplies X values; otherwise, sampling interval of the Y column or row number is used.
Select required data.
Select Plot > Basic 2D: Double-Y Column from the main menu.
2Ys_Col.OTP (installed in the Origin program folder).