I need help with all 3D thing please

Hello i am trying to develop a game, and now i am learning about the 3d "thing". I have design my 3d object and i am trying to load it the game. But once done i cant see it. I have a state with one background, and i atach to it the state where there is the 3d object. But when the game is started it is not viewed. However if i atach the state wich contains the 3d model directly to the "root" (the background is not load), then i can see the object over a black background. I have been looking for a good tutorial related with 3d but i could not find it. Could anyone help to me please?. Thank you.

try the wiki and look at the flagrush tutorial

I am looking at that tutorial but i have some doubts about how to place the object what i need to see it correctly, is there any place where i can solve my doubts?