Select at least two columns of values or a range of values from at least two columns. Plot designation does not matter; selected columns will be treated as Y columns.
For information on the customizing allivial diagrams, see these topics:
Alluvial.otpu (installed to the EXE folder of Origin)
To describe the details about this kind of graph well, let's call the little black rectangles "nodes", the colored areas (linking nodes) "links", and the vertical groups of nodes "steps".
Alluvial diagrams represent weighted flows among nodes. In the source data, each row of the dataset becomes a series of linking flows, each column defines a step, the cells with same value defines a node.
In a alluvial diagram Origin created, you don’t need define directly the height of the nodes. The height of nodes and the width of flows is therefore linked to the number of lines in the dataset containing the same couple of nodes. Flows coming from and going to the same couple of nodes are grouped.