The Tree widget is fairly picky, so do an output of a Network take a look at how that is structured.
you'll note it always starts with a top node that has the To but no From
and then the children under that in order, before switching to the next top node.
So if you mimic that structure, and then make sure you configure the properties of the Tree Widget appropriately, you should be fine.
As an example, you could create a DataTable, and give data like on left:
Then you could set configuration in the Tree widget as:
Finally when you run the mashup, the Tree widget will load the data properly(as shown on top right picture). make sure that you have the the parentIs properly set which should be the id of its parents' Labelfield, and the leave the root node's parentId as "root" or something, and finally set it in the Tree widget configuration in accordance.
Hope this helps.