Select at least one Y column (or a range from at least one Y column). Ideally, select at least two Y columns (or a range of at least 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: Stacked Lines by Y Offsets.
Click the Stacked Lines by Y Offsets button on the 2D Graphs toolbar.
OFFSETSTACKY.OTP (installed to the Origin program folder).