Shaiv Darshan is also known as "Shivaagam", "Shaiv Mahaatantra", "Paashupat Darshan". Its principles are described in Naarad Puraan, 1/26.

According to Shaiv Darshan, there are three materials (Pashu - which is bound, Paash - with which to bind, and Pashupati - Shiv); and four means (Vidyaa, Kriyaa, Yog, and Charyaa - Charyaa mans activities which are regularly done).

When one takes a Mantra methodically from Guru, is called Deekshaa. This Deekshaa cannot be completed without the knowledge of Mantra, Mantreshwar and Vidyeshwar etc animals. One can identify Pashu, Paash and Pashupati only from this knowledge. Therefore to get Deekshaa, the cause of Paramaarth, the first step is "Vidyaa". According to various learned people, Deekshaa is of various types. Thus all the activities performed involved in taking Deekshaa, the second step, is called "Kriyaa". But without Ashtaang Yog one cannot achieve his goal, that is why "Yog" as the third step, is necessary. And Yog is completed only when people do Shaastra prescribed Karm, and abandon Shaastra prohibited Karm. Thus all these Karm (prescribed and prohibited ones) are called "Charyaa" - the fourth step.

Pati or Pashupati
Only Shiv is Pati or Pashupati. Maheshwar has five jobs to do - creation, maintenance, destruction, deterioration, and to bestow Var. Although Vidyeshwar etc become like Shiv, but still they are not independent, they are subordinate to Parameshwar. Where Shiv is described with attributes for worship, there also he is not shown in physical body. Because he is pure that is why his form is Shakti (Power). Maheshwar's form is described in Mantra form in Upanishad.

Pashu
Pashu is the name of Jeevaatmaa or Kshetragya. Pashu is called whatever is bound by Paash (by which something is tied). This Jeev is bound by Paash, that is why he is called Pashu. In fact Jeev is not an atom, but is widespread and immortal - this is clearly stated in Shaiv Darshan. But this Jeev, in this state - in Pashu (bound) state, is equipped with limited powers, still he is not non-doer like the Purush of Gyaan Yog, because after he is freed from Paash, he also becomes equipped with unlimited Gyaan and action powers.

Pashu is of three types - 
(1) Vigyaanaakal - Who destroys the fruits of his Karm by Jap, meditation and Sanyaas or by enjoying after knowing Paramaatmaa's form; and because of destruction of Karm, who has no binding of body or Indriyaan, he is called Vigyaanaakal. He is bound only with Mal (A-Gyaan, or ignorance, or Maayaa) Paash. Dirt Paash is of three types - Aanav Mal, Karmaj Mal, and Maayeya mal. Only Aanav Mal remains in Vigyaanaakal. Because he frees himself by Vigyaan that is why he is called Vigyaanaakal.
(2) Pralayaakal - Whichever Jeevaatmaa's body and Indriyaan are absorbed in Pralaya Kaal (time), he does not have Maayeya Mal, but remain only Aanav and Karmaj Mal. Because he is destroyed in Pralaya Kaal that is why he is called Pralayaakal.
(3) Sa-Kal - Whichever Jeevaatmaa is bound with all the three Paash - Aanav, Maayeya and Karmaj; he is called Sa-Kal (Sa means "with", and Kal means "aspects", so Sa-Kal means "with all aspects", means completely)

Paash
According to Naarad Puraan, Paash are said to be of five types  - Malaj (born from Mal), Karmaj (born from Karm), Maayeya (born from Maayaa), Tirodhaan - Shaktij, and Binduj. Modern Shaiv Darshan mentions four types of Paash - Mal, Rodh, Karm, and Maayaa. Rodh power and Tirodhaan power are the same. Bindu is a form of Maayaa and can be known as Shiv Tattwa. 
(1) Mal Paash - Whatever covers the natural knowledge and action power of Aatmaa is called mal (A-Gyaan, or ignorance, or Maayaa). This Mal not only covers him but also leads him to do bad Karm. 
(2) Rodh Paash - Whatever capacity a material has in it, is called Shiv's power, for example, burning power in fire. In whatever kind of material it resides, it takes the same form - good or bad. Therefore when this power of Paash covers the real form of Aatmaa, it is called "Rodh power" or "Tirodhaan power". In this state, Jeev considers his body as Aatmaa (soul), and is busy in nourishing his body, not in uplifting his Aatmaa.
(3) Karm Paash - All Karm done with the desire of fruits are called Karm Paash.
(4) Maayaa Paash - All become absorbed in whichever power at the time of Pralaya; and are created at the time of creation, is called Maayaa Paash. [This points out towards the Ultimate Power, because He is the only Power in which all become absorbed at the time of Pralaya and are created at the time of Creation.]

Therefore the Pashu (this body), bound with these Paash, cuts them by Tattwa knowledge, then only he attains Shiv or Pashupati status.

Deekshaa
Deekshaa is the means to attain Shiv. Parameshwar, living in the body of Guru, helps Jeev to attain Shiv by giving him Deekshaa. Whatever body is taken by this Jeev, it is made up of eight Tattwa - Panchbhoot, Man (mind), Buddhi (intellect) and Ahankaar and is called "Puryashtak". This Puryashtak body is made up of 36 Tattwa - Seven Tattwa (Kalaa, Kaal, Niyati, Vidyaa, Raag, Prakriti, and Gun), Panchbhoot, Panch Tanmaatraa, 10 Indriyaan, four hearts, five subjects of five Indriyaan. Whoever Jeev do Punya Karm, Bhagavaan appoint them as Bhuvaneshwar or Lokpaal.