If you get plenty of sunlight then transfer all the lentils in a large plate and put them under the direct sunlight for 2 to 3 hours at least. This step is must to avoid any moisture in lentils.
If getting sunlight is hard for you then transfer all the lentils in a pan and dry roast them for 5 mins on medium flame.This step is must to avoid any moisture in lentils.
cool it down completely.
transfer into the mixer jar and churn.
churn to a slightly coarse powder.
store the powder in air tight container and use as required.