In WED press mouse right button and select Add:
In the submenu press Add region:
The path will appear on the level as a small selected red box:
Select Vertex mode as shown on the picture:
Once you've selected Vertex mode, just press near by the path, and you'll notice that it will create nodes, which are linked to the original path "box" (cause it was selected at the beginning, you can select any node and start creating another outflow:
You can edit nodes which you've just created, to do that while you are in the Vertex mode, press and hold the node (make sure you don't miss it ), as it become red you can freely move it around: