Using the Type drop-down list, you can choose the terrain type, from Custom, Mountain, Mars, Moon, Desert and Polar.
Use the gradient to define the colors of the terrain. The left-most color is the color of the lowest regions, while the right-most color is the color of the peaks.
Height scales the terrain in the Y direction of the texture axes. For example, with a value of 50, the fractal would take up half of the object (provided that the texture geometry has been adapted to the object).