Question

how to make easy and attractive model of step farming

Answer 1

you could put layers of something like thermocol /foam paper in a manner that it looks somewhat like this
then paint it accordingly green
if thats a foam paper then use fevicol/feviquik to paste but if your using termocol then use toothpicks or high sticking gum.
if want to add more details then you could make a clay farmer model and add trees in middle like given in the pic