Glad you asked...
First you will need to make a mountain shape, which you can do with a circle of poster board. Cut one slit into the poster board circle that goes to the center of the circle. Roll up like a cone and secure with tape in several places. Cut the tip of the cone so that your mountain is not pointy. Now, you will need to make the paper mache. Add a couple of cups of flour to a large bowl or pot. Add enough water to make a batter about as thick as pancake batter, stirring so that there are no lumps. Make some strips from newspaper - lots of hem. Dip the newspaper into the flour/water mixture, scrape the excess off, and start wrapping around the cone. Do several layers that cover the entire cone, and let dry overnight. If needed, you can add several more layers after the first have dried. When you are done with the paper mache, and it is completely dried, you can paint with poster paints, add little twigs, pebbles, or mini-grasses and leaves from outside to embellish.
Then again, this answer might help you...
First, make a model of the mountain by using wire or cardboard. Wet the strips of paper in the glue mixture and apply it to the model. Once it dries, remove the model and paint the molded paper to resemble a mountain.

