How to turn off backface culling for terrains?

How do I render both sides of the terrain? I am not familiar at all with shaders But I do know its something simple. How do I just set the terrain? Please be specific. Thanks

You can either turn off backface culling in a shader or you can duplicate the polygons and flip the normals. If you turn off backface culling, the normals will not be correct. Read here for more information.