Take ragi in a vessel and wash it by rubbing well with your hands. It has lots of muds so repeat the process 2 to 3 times unless it is clean and get rid of all muds. Keep aside. Wash green gram well in running water twice & set aside. Then soak both ragi and green gram in clean separate vessel with water for 8 to 12 hours. Keep it covered (with provision to some air to enter) while soaking. After 8 to 12 hours, open.
Then drain the water completely from both. Transfer the drained green gram & ragi to a clean white cloth or cheese cloth for sprouting. Place the cheese cloth with green gram & ragi in a colander.
Tie it up with all four corners and keep it undisturbed for another 12 hours for sprouting. After 12 hours, open the cloth carefully. You could see the tiny sprouts in ragi. Green gram also gets sprouted well. Transfer the sprouted ragi & green gram to a plate and dry it under sun or shade for 8 to 12 hours.
In the meantime, wash rice well in running water and drain the water completely. Dry the rice under sun or shade for 2 to 4 hours or until it's completely dry.
After sun drying the ragi, dry roast the ragi in a pan in low flame for 5 minutes or until it's toasted. Remove from the pan and cool it down.
After sun drying the green gram, dry roast the green gram in a pan in low flame for 5 minutes or until it's slightly crisp. Remove from the pan and cool it down.
After sun drying the rice, dry roast the rice in a pan in low flame for 5 minutes or until it's little puffy. Remove from the pan and cool it down.
Take the roasted ragi, green gram and rice to a dry mixer jar and blend it to a smooth powder. Sieve the powder well. Cool it down and store in a air tight container.