Select 6 columns at least, the column designation should be XYYYYY.
First 2 columns are used to definded the node position on the map; Third column is used to define the node lables; Fourth and Fifth column are used to define the link by node lables from 3rd column, or 0-based index of source and target nodes. Sixth column is used to define the weight of the links.
For information on the customizing allivial diagrams, see these topics:
sankeyMap.otpu (installed to the EXE folder of Origin)
Sankey Map is an enhanced variety of Sankey diagram，which plots the nodes as bubbles and positions the node bubbles with map coordinates on a map.
For this kind of Sankey on map, Origin supports to add links from/to any side of the nodes which are shown as bubbles. By default, a link from node A to node B need to calculate horizontal and vertical distance between node center:
For a link special point(double-clicking on a link with CTRL pressed), you are allowed to specify which side of node two ends should link to.