You can do this Shabar mantra chanting for 11, 21, 31, or 41 days, the area and time of mantra chanting should be exactly the same for the quantity of days you want to do sadhana. You should utilize Rudraksha or Tulsi rosary to chant the mantra. It is https://das-mahavidya72716.blogminds.com/most-powerful-sarv-karya-sidh-shabar-mantra-karya-siddhi-shabar-mantra-most-powerful-shabar-mantra-no-further-a-mystery-29765368