Documentation

Target Nodes

This field contains the ID of one or multiple target nodes (also known as “child nodes” or “To nodes”). Target nodes are nodes that succeed the specific data point in the hierarchy.
 
For example, if you want to create a relationship between nodes A and B where the latter succeeds the former, you must define B as the target node of A. 

source_nodes

By default, Node IDs will also be used as display names on the chart. If you wish to use custom display names for the nodes (with spaces), you can use the Target Node Label field.