Soak Kodo Millet and Urad Dal in water for about 4 hours. In a mixer or grinder first blend the Urad Dal like how we grind for dosa to a smooth consistency and next grind the Kodo Millet till smooth.
Mix both the Urad Dal and Kodo Millet and keep it in the same bowl allow it to ferment overnight or about 6 hours. Next day or while preparing the dosa add the required salt and water and bring it to the dosa batter consistency. Mix everything together and heat a dosa Tawa.
Take a ladle full of batter and spread on the dosa Tawa. Drizzle ghee and cook on both sides till fully cooked. Kodo Millet dosa is now ready to serve.