I would never call you stupid, I didnt create a tutorial, so I am the stupid
Please download the newest version and then open it and select File -> new -> cube -> Empty/Full
Then you have 20 Height.
If you dont open a File with it(rightclick -> open with -> ebe editor), you always have a Floor as standart, so beginners can start with simple things and not must concentrate on 3D thinking
I hope I could help
My dream is to develope games, which makes fun when I create it and fun when other people play it.