Blender: A "simple" !? winter scene

[winlang]

This tutorial was a wonderful instruction - until I came at the point
to add a plane:
I had made an additional window with the camera-view, and have to
see that the plane cut across my wonderful snowman and trees.
The man, the trees and the plane were spread of 3 layers (all marked)
The catastrophe begann: In front-/top-& side-view was nothing to see anymore, the camera-view shows all objects.
How can I get an object again that is lost into the nirvana.

[Nothing]

Umm yes simple..
I started using Blender only a few days ago, i have been curious about it for some months now. I'm still getting the hang of Blender itself and the interface and how it behaves..but I am getting there and DuskBlue's tutorial on a simple winter scene is helping me see some small essential things that aid the learning process..I thank you DuskBlue for your effort in this tutorial. I can't wait for my Blender skills to mature but winlang's problem seems to be simple user error we all have them when we're first starting out, learning the Undo keyboard shortcut is key to erase mistakes, this error has nothing to do with the simplicity of DuskBlue's tutorial. I myself spent like at least an hour and a half on this messing around, following the tutorial closely, except the texture on the trees I somehow missed the Map Input and Tube button selection and they looked interesting..., but this was my error and I got it done and i know more for it. Just remember that anything is difficult until you understand it. If you have to do something over again completely, it will help solidify the procedures in your mind when you're a newbie at it.