Heat 1 cup of water and add 1/4 cup of Ragi (finger millet) flour, salt and make porridge and remove from heat.
Now add rest of the ragi (finger millet) flour (sprinkle and add to avoid lumps) ,onion, green chili, coriander leaves to the porridge and make a soft dough like you for chapati by adding water as needed.
Now make balls out of the dough and flatten them with rolling pin.
Heat a skillet coat with generous amount of oil. Now cook both sides of the raw dough until they are cooked and serve. i.e. cook like you cook chapati.