http://www.beamng.com/threads/13464-Mashup-Greyroom-1-Greyroom-2-Greenroom-Whiteroom Scroll down, there's a map called green room. That's what you're after.
I DON'T KNOW - - - Updated - - - oh thanks ,very thanks !!! but i have a question, i can boulid other green blocks on this map ?
You can add more cubes to the map by opening the editor (F11), switching to free camera (Shift +C) and selecting a cube, then while holding shift, move the cube. You can place this cube wherever you want, plus you can rotate and scale with the other tools on the left of the screen.