At this site, I was asked a private question about how to use the poseable streams. Here is an image from the first stream's product display that should provide an answer to that very good question.  Please click on the image to expand it to a comfortable view level.

Essentially, you move the stream into general postion in your foreground area. Select the first joint and fine-tune the placement. Typically, this joint will not be visible in the camera view if your scene is designed to be looking up the stream. Instead, this joint will be below the camera and closer to the viewer.

Then, starting with the second joint, rotate or elevate that joint. Working with each joint, moving away from the camera and toward the far head of the stream, shape the stream as you intend it for the final stream.  That is, create bends or changes in elevation, if that is appropriate.

The reason that you start with the joint nearest you and the camera, is that the first joint is an "anchor" joint. Each subsequent joint further up the joint chain moves the remaining part of the poseable stream, without moving the joints further down the joint chain - and without moving the portion of the stream that you have already moved into position. 

 

Now, you can load or import other objects and place them around the stream to form the bulk of the scene. These objects can be small patches of terrains, stones, plants, or objects in the stream, such as fish or boats. You also can add any of the River Rapids pieces to create rocks and foam flowing around the rocks.

That is all there is to the process.