I just purchased IRAY, so I’m still learning but I tried to add a scene that had water and trees in it ,everything  else would add in the selection list but it would not let me add the trees in the water for some reason they would not go to the selection list. Can somebody help me with this?

Iray does not render water. You have a choice to setup a plane with water texture/video
As for trees, as far as I remember, they cannot be selected. If they are in the scene they are pre-selected internally.

Thanks ,