Hindu cycle of the universe
According to Hindu philosophy, the universe (or multiverse) never came to be at some particular point, but always has been, always will be, but is perpetually in flux. Space and time are of cyclical nature. This universe is simply the current one, which is in flux and constantly changing, when it finally ceases to manifest, a new one will arise. An interesting parallel to these ideas can be found in the ekpyrotic model of the universe. This concept is also accepted by Buddhist Dharma.
(Shiva) is the supreme power, whose (Shankar) is just a part, who was given form on request of Vishnu and Brahma, because they believed they couldn't maintain the balance of the universe alone, without Lord Shiva's supervision, and he, (shiva) After creating Vishnu and brahma and settling a balance in the universe wished to go for eternal meditation, henceforth, creating Shankar (often confused or considered same as Shiva) who was assigned lord shiva's power and entity. And thus maintaining the balance of the universe.
Thesis of creation
According to Vaishnava scriptures, at first there was only MahaVishnu, who rests on the eternal ocean. When he is asleep,nothing exists. There is only pure consciousness,an infinite potential. With his awakening, there is light and life. Out of his navel comes out Lord Brahma who assumes the duty of creation. In his first act as the creator, Lord creates four sages Sanaka, Sananda, Sanatana and Sanat-kumar,who do not have worldly views due to their devotion to Narayana or Maha-Vishnu, the supreme godhead. So out of his frustration and anger was created Rudra or Lord Shiva. Lord Shiva assumed the duty of destruction at the end of the epochs. Thus the Holy trinity assumed their duties for an endless cycle of creation, preservation and destruction.
As per Shaiva scriptures, at first, the ultimate truth "Brahman" was Shiva without any birth or death. Vishnu is formed from the vaamanga of Shiva or the left body. Shiva is the extreme male power of the universe. He is the destroyer or annihilator of the universe. From him manifested the extreme female power of the universe Sati. Then the preserver of the universe Vishnu took three forms, Karnodakashayi Vishnu or Maha-Vishnu, Garbhodakashayi Vishnu and kshirodakshayi Vishnu. Maha Vishnu has several Garbhodakashayi Vishnus in the spiritual sky (the ocean of Karana). Each Garbhodakashayi Vishnu exhales and inhales and with each breath a Brahma is born who lives for 100 Brahma years and dies with the breath of Garbhodakashayi Vishnu. Each Brahma creates a universe which comes to an end with partial annihilation. After several Brahma years the annihilation of the entire universe takes place at the last stage, the dissolution of the whole karan sagar by Shiv with Tandav and this cycle again begins. This cycle of formation and annihilation is seen in Hinduism.
Hindu scriptures hold that Lord Vishnu, the protector and caretaker of all creation, sleeps in the middle of a vast ocean on the giant snake Sheshnaga. When the cycle begins, Lord Brahma is born out of the 'lotus', an allusion to the kamal[lotus] which is the origin of all life. This 'lotus' comes out of the navel of Lord Vishnu. The lotus is known as Brahma Kamal. The first sound of Lord Brahma is Om, the origin of all creation.