strange, I found 3dgs very easy to start with, it was the main reason of selecting this instead of other engines, as I had no real knowledge of 3D game making at all... just did the tutorials and read the AUM magazines to get the basic info to start, and read the corresponding parts of the manual when I started to make my own things.

the easiest to start with WED and draw a level from blocks, import prefabs, terrains and models by a few clicks, check the demo levels available how they are built, and everything should be okay and will be easy to move on.

or use my editor for outdoor levels, and check the example projects you get with it a couple of free models and terrains. I think it's okay for beginners, unfortunately the documentation is not finished totally.