The Source tree pane is located on the left side of the editor and shows the tree of nodes that corresponds to the XML Schema, which is used as the basis for the incoming message.
The nodes that correspond to schema elements are marked with an icon representing green angle brackets ().
The nodes that correspond to attributes are marked with an icon representing a blue box ().
A node contains an element's or attribute's name and a type.
To create a mapping, select a node and drag the pointer to an XPath function connector in the Transformation pane or to a node in the Destination tree pane.