Click on the Terrain object icon and create a terrain(mountain).
Click on the little E.
Drag the color slider "}" down. If it doesn't appears, click on the icon to the left of the downward-pointing arrow at the top of the Terrain Canvas window.
Select a object to place.
Select the Solid.
Click on the check mark in the lower right corner.
Drag and change the object size.
Change the camera angle to From Top.
Drag and change the position.
Select the Copy from the Edit menu.
Select the Paste from the Edit menu.
Move the pasted terrain and adjust the position.
Rotate the terrain and adjustl the direction.
Change to the Camera View.
Adjust the position and size.
Select the All Select from the Edit menu.
Click on the little M.
Click on the small right arrow to the right of the preview window.
Click on the "PLAIN and TERRAINS" category (1), the Grand Canyon material (2) and the check mark (3).
Click on the check mark in the lower right corner.
Click on the word Sky&Fog.
Specify the sun position, the cloud height, the cloud color and etc.
Render.