The highest of the Nine Ways, Dzogpa chenpo khyabpar yang tsewai thegpa (rDzogs pa chen po khyad par yang rtse ba'i theg pa) - "the Highest, Unsurpassable Path of Great Perfection" - contains teachings on Dzogchen. This is the Path which leads to the full realization of Buddhahood (rdzogs sang rgyas pa). From the perspective of Dzogchen, none of the other paths arrive at this complete realization since their Views are based on the principle of Two Truths (bden pa gnyis) and all of them, including Tantra, use consciousness (shes pa) to attain their realization. Therefore, the other Eight Ways are all provisional (drang don) and lead to the realization of some aspects of the final truth, but they are never able achieve it ultimately, as it is. Dzogchen, on the other hand, does not rest on the Two Truths but instead is based on a direct understanding of the Nature of Mind (sems nyid) beyond the use of any consciousness. Here, the Nature of Mind is understood as being self-perfected (rang rdzogs) and aware of itself. This is what is called Self-Awareness (rang rig) or simply Rigpa (rig pa). The Nature of Mind is non-dual (gnyis med), inseparable (dbyer med), both the aspects of emptiness and clarity are primordially present (ye gnas gsal stong dbyer med), and it is primordially liberated (ye grol). This Nature of Mind pervades all phenomena, but is peculiar only to sentient beings, i.e. beings endowed with mind or consciousness (sems can). Inanimate objects do not have the Nature of Mind since they have neither mind nor consciousness. Neither is this Nature of Mind one indivisible Nature common to all sentient beings similar to the primordial, universal consciousness such as is found in Brahmanism or Hinduism where it is illustrated by the metaphor of a single moon reflected in many bowls of water. One being's Nature of Mind is not another being's Nature of Mind, even though the Nature of Mind of every being is endowed with the same qualities and characteristics: emptiness, clarity and non-duality.
THE BASE (GZHI), THE PATH (LAM) AND THE FRUIT (BRAS BU) OF DZOGCHEN
This Primordial State (gnas lugs) or Primordial Base (ye gzhi) represents the Primordial State of Buddha (ye sangs rgyas pa), is primordially present in all sentient beings (sems can), but remains unrecognized. In other words, sentient beings are ignorant of this Primordial Base, and it is this ignorance (ma rig pa) which is the cause for Samsara or Khorwa ('khor ba). Dzogchen teachings recognize three aspects of the Primordial Вase: its Essence (ngo bo) which is Emptiness (stong pa) or Primordial Purity (ka dag); its Nature (rang bzhin) which is Self-Awareness (rang rig) or Clarity (gsal ba); and its Energy (thugs rje, literally 'compassion'), which represents the primordial inseparability of Self-Awareness and Clarity (ye gnas rig stong dbyer med) and has the quality of being uninterrupted and non-stop (ma 'gag pa). These three aspects are also known as the Three Bodies of the Buddha of the Base (gzhi'i sku gsum).
By practising the method known as 'searching for the mind' (sems tshol) and other preliminary practices peculiar to Dzogchen, such as Khorde Rushen ('khor 'das ru shan, 'separating Khorde/ Samsara and Nyangde/Nirvana') and Semdzin (sems 'dzin, 'beholding the Nature of Mind'), both of which lead to an understanding of the difference between the mind (sems) and the Nature of Mind (sems nyid), the student comes to understand the Base described above, which is common to both Tantra and Dzogchen. The Path of Dzogchen as such begins with a Direct Introduction (ngo sprod) to the Nature of Mind; this is given by an authentic Dzogchen master. The Direct Introduction enables the student to gain a direct experience (nyams) of the true Natural State, and this is the base for all subsequent practice. The main practice consists of two inseparable aspects: Trekchö (khregs chod, 'liberation of the taut state') and Thögal (thod rgal, 'leaping over the vertex of visions'). These two aspects of practice are linked to the two inseparable qualities of the Primordial State: Kadag (ka dag) or Primordial Purity which corresponds to emptiness (stong), and Lhundrub (lhun grub), or Spontaneous Perfection, which corresponds to clarity (gsal ba).
Trekchö is continuous contemplation in the Natural State of the Mind (sems nyid) free from the influence of any kind of mental activity or consciousness (rnam rtog, shes pa), free from any kind of modification (ma bcos pa), simply leaving it as it is (cog bzhag). As a result, the practitioner is able to remain in the state of contemplation twenty-four hours a day without being distracted. This practice works with the aspect of Emptiness (stong pa).
Thögal practice works with the aspect of Clarity (gsal ba). Three main methods are used here: dark retreat (mun mtshams); contemplation of the 'sky' (nam mkha') or the unification of the three spaces (stong ba gsum sbyor lag len); and contemplation of sunlight (nyi 'od), Thögal itself. Thögal practice works with the visions (snang ba) which arise from the Primordial State and develop in four or five stages (snang ba bzhi, snang ba lnga).  The practice of Thögal enables the practitioner to gain an unequivocal realization that all mental phenomena and external objects are none other than Empty Form (stong gzugs). 
Once the Dzogchen practitioner (rdzogs chеn pa) arrives at the final stage of Thögal, s/he realizes the Three Bodies of the Buddha of the Fruit ('bras bu'i sku gsum):
Excerpted from D. Ermakov, Bön, for the Encyclopaedia of Buddhist Philosophy (2011). Translated from Russian by C. Ermakova.
1. The mind (sems) is utterly liberated into the Nature of Mind (sems nyid) and Bönku (bon sku), the Body of Absolute Reality, manifests;
2. Without going through the process of death, the physical body (lus) dissolves into the essence (snying po) of the five elements ('byung ba lnga) and the Rainbow Body of the Great Transfer ('ja lus 'pho ba chen po) manifests. This is the Body of Perfection (rdzogs sku);
3. The capacity to emanate many manifestations on the physical plane in accordance with the needs of sentient beings arises simultaneously. This is Trulku (sprul sku), the Body of Emanation. 
The realization of the Three Bodies of the Fruit of Dzogchen is the full and final realization of the state of Buddhahood (rdzogs sangs rgyas pa) according to Yungdrung Bön.
Copyright © Dmitry Ermakov, 2012
 The Oral Tradition (from the country of) Zhang Zhung, Zhang Zhung Nyengyud (Zhang zhung snyan rgyud), describes five stages; other cycles of Bönpo Dzogchen describe four.
 Unlike the Nyingma version of Dzogchen, Trekcho and Thögal are taught together in Bönpo Dzogchen, since they represent two inseparable aspects of the Natural State. For example, the most ancient of Bönpo Dzogchen teachings, the Zhang Zhung Nyengyud includes the methods known as Trekchö and Thögal in other teaching cycles, but here, the terms are not mentioned per se and the simultaneous practice of the two aspects is simply referred to as Clear Light ('od gsal).
 Gyaltsen, Shardza Tashi. Commentary by Lopon Tenzin Namdak, Heart Drops of Dharmakaya: Dzogchen Practice of the Bön Tradition (Ithaca: Snow Lion Publications, 1993), pp. 77-83.