On the first night of Navratri, on the New Moon, we worship Parvati Ma, the consort of Shiva, known on this occasion as Shailaputri, “Daughter of the Mountain” which is what the name Parvati means.
You can use this stuti for worshipping Her: YA DEVI SARVABHUTESU MAM SHAILAPUTRI – NAMASTASYAI NAMO NAMAH
This is also the day we establish the “kalash” the vessel for holding holy water (Ganga Jal if possible – otherwise water from an important river, or a spring, or a creek) into which we put fragrant oils, betel nut, coins, unbroken rice, and other auspicious items, and invite Ma Durga, and all the Gods and Goddesses, Yogis and Yoginis to inhabit the vessel for the duration of the nine days, and bring us blessings.
We also make an altar consisting of a clay dish with 3 layers of sand (of nine colors if possible) into which we layer barley grains that will sprout over the next nine days.
Cover the holy water vessel with a coconut surrounded by 5 large leaves (mango if possible) and place it in the middle of the altar of sand and barley. Icons and pictures of Durga, Lakshmi, Ganesh, and any other favorite or family deities may surround the altar. Having done all this, invoke the Mother Goddess, ask Her for her darshan and blessings.
This is a simple way to begin the Navratri observances.