Srishti is a main topic in the puranas and in the Devi Bhagavata Purana it is explained from the angle of Prakriti. Goddess Devi reveals the truth of srishti to Brahma, Vishnu and Siva when out of Her Sankalpa they come to Her abode. All these details are conveyed by Brahma to Narada by way of clarifying many of the latter’s doubts on these esoteric matters, pointed out Sri K. Srinivasan in a discourse.
She explains in detail the special aspects of the gunas, Satva, Rajas and Tamas. These gunas inhere in each and every aspect of creation in varying proportions. In the Trimurtis too, the three gunas enable them to fulfil their respective roles in creation, sustenance and samhara. Para Prakriti is the Nirguna Brahman, all pervading and in a state of balance when the gunas are not active. This is before creation happens.
So, Nirguna Brahman is not the creator or the cause of srishti. Srishti happenings are allied to the Saguna Brahman. It is only with the help of Maya that srishti happens. The Upanishads speak of Sat as eternally existing without a second. Then Maya is summoned to assist Ishwara and together they work to bring about Srishti. From Prakriti, Mahat is born and then Ahamkara. Then the five elements akasa, air, fire, water and earth are created and this is followed by jiva srishti. All beings and objects are then brought to life by the pervasive power of Shakti. Maya is the blend of the three gunas and these are in a disturbed state at the time of srishti.
This leads to the evolution of beings and activities in the world. Jiva srishti is to enable the jivas to exhaust their karma. After the specified period of time, srishti is followed by Pralaya, a state of non disturbance. Srishti and Pralaya reflect the waking and sleep states at the cosmic level.