The permanent cycle of the five-fold duties consists of
“Sarga” is the creation of the world – observed in Earth
“Sthiti” is its maintenance; – in Waters
“Samhara” is the annihilation; – through fire
“Tirobhava” is the removal and concealment – Wind
“Liberation” (from the cycle of birth and death) Is blessing (observed in firmament). (bliss – people are using this so loosely nowadays that its almost like they are liberated while they are alive.
The first four activities concern the evolution of the world and the fifth one is the cause of salvation. These activities are observed in the five elements by devotees-
Sarga (creation) in the Earth, Sthiti (main- tenance) in the waters, Samhara (annihilation) in the fire, Tirobhava (concealment) in the wind and Anugraha (liberation, the blessed state) in the firmament. Everything is created by the Earth; everything flourishes by virtue of the waters; everything is urged by the fire, everything is removed by the wind and everything is blessed by the firmament. Thus intelligent men must know the same.
In order to look after these five-fold activities Shivas has five faces, four in the four quarters and the fifth in the middle. creation is taken care by Brahma and maintenance by Vishnu.
Similarly, the other two activities (annihilation and concealment) have been assigned to Rudra and Mahesa.
The fifth one of Anugraha (liberation) cannot be taken up by any other.
Rudra and Mahesa have been doing their duties diligently and that’s why we see more annihilation.
The syllable “A” came first from northern face; the syllable “U” from the western ; the syllable “M” from the southern and the Bindu (dot) from the eastern face. The Nada (mystical sound) came from the middle face. Thus the complete set cropped up in five-fold form. Then all of them united in the syllable of “Om”. Now to relate back to Bindu and Nada. Bindu is the tiny atom and Nada is the wave form. When Bindu is approached at a high speed by the waveform, it will release infinite energy which is what Einstein wanted to prove.
The two sets of created beings-Nama (name) and Rupa (form) are pervaded by this mantra. It indicates Siva and Sakti.
From this also is born the five-syllabled mantra (Na-ma-ssi-va-ya). It indicates all knowledge.
From the five-syllabled mantra the five mothers were born. The Siromantra is born of that. The three-footed Gayatri (Tripada Gayatri) also came out of the four faces.
The entire set of Vedas and crores of mantras were born of that. Different things are achieved through different mantras but everything is achieved through Omkara alone.
By this root-mantra, the very enjoyment as well as salvation is achieved.
Now as to Why one stays awake on Shivaratri:
There was once a poor tribal man who was a great devotee of Shiva. One day he went deep into the forest to collect firewood. However he lost his way and could not return home before nightfall. As darkness fell, he heard the growls of wild animals. Terrified, he climbed onto the nearest tree for shelter till day-break. Perched amongst the branches, he was afraid he would doze and fall off the tree. To stay awake, he decided to pluck a leaf at a time from the tree and drop it, while chanting the name of Shiva. At dawn, he realized that he had dropped a thousand leaves onto a Linga to keep himself awake, the tribal plucked one leaf at a time from the tree and dropped it below which he had not seen in the dark. The tree happened to be a wood apple or bel tree. This unwitting all-night worship pleased Shiva, by whose grace the tribal was rewarded with divine bliss.
Copying this, many others followed the tradition to get Lord Shiva’s blessings on this new moon night.
The whole idea why this was mentioned in Puranas is to educate people that “with true devotion, you can attain God”. But many people follow it literally to be doing only on that night with bel leaves to get His blessings. God is everywhere, even inside humans, dogs, birds, trees. When we experience this omnipresence of God in whatever form, our Ego (Made up of Sattva, Tamas, Rajas gunas) gets diminished and we accept the greatness of God.