working with Nodes to composite scene question

am using Blender 2.72… am trying to create a stream of water over rocks… I used texture painting on the landscape creating an image… I have used vertex painting on some of the rocks and a tree branch… this is nothing fancy … am learning Blender so trying to learn the basics of it … I want to create water flowing over the rocks… I can do that with the fluid system, but all I can see is using the Cycles render to make the water appear as water… but using the cycles render, my landscape don’t appear with the painted image on it and I don’t know which nodes to use so that It will all come together… the rocks, the plants, the landscape and the water…
Is there a good tutorial I can watch that tells me how to use the nodes to create the scene… some of the tutorials I watch, they go over the nodes too fast and I don’t know which ones they are using or how to hook them up… need a good tutorial I can watch and take notes from…

thank you
have a good day

Your question doesn’t have enough detail to guess exactly what you want to do, but perhaps you simply need an alpha over node. This is used to mix an image with alpha, or transparency (turn on transparency in scene render settings) with a background image.