The Vajrayana or the Tantric Vehicle is the same in philosophy as the Mahayana or the Great Vehicle
but differs vastly in the actual techniques of practice. Because it is equivalent to the Great Vehicle
in aim but more effective in practice, Milarepa has said:

“To leave the inferior path (of the Small Vehicle) and (really) enter the Great Vehicle,
one must enter the path of the Peerless Vajra Vehicle (anuttaratantra).”

All elements of the Great Vehicle path are present in the Tantric Vehicle. The five paths and ten bodhisattva stages are condensed into two stages: generation and completion.

Short introduction to Anuttarayoga tantra yoga:

During the extensive generation phase, the yogi first purifies himself with guru yoga and generates the mind aimed at enlightenment. Then the currents, channels, and centers of the tantric psycho-physiological system are developed and mastery over their functions sought through the physical and mental exercises of the path of the method.

The deities of the Tannic Vehicle’s extensive pantheon, the male and female personifications of psychic processes as herukas (male buddhas) and dakinis (female buddhas) are “generated” by the yogi through the practice of controlled visualization until their reality overshadows that of the superficial apparent world.

This generation stage leads the yogi to confront the processes embodied in each deity and to transform his own inner and outer environment into the divine realm of that deity. In particular, the yogi forms a relationship with one specific deity, known as his “personal deity” (Skt. Ishtadeva/i; Tib. yidam), through practices and visualizations associated with that deity.

When the yogi is able to visualize his personal deity to the point where the visualization seems to have a life of its own,
and when he is able to see his environment as divine, he then practices the “divine pride” of direct identification of his own body and mind with those of his personal deity.

When the reality of the apparent world has been overshadowed by the intensity of his visualization and direct experiences of insight into natural ground reality, the yogi then enters the completion stage where the illusory nature, or voidness, of his visualization, can be realized, and with it the voidness of the ordinary, apparent world.
This is due to the fact that the apparent world is by nature an illusory “visualization” derived from compulsive
attachment to ingrained preconceptions about the nature of things.

Realization of voidness is not the only result in the completion stage, for owing to the previous generation stage, the yogi is endowed with powers (of his yidam) and skillful methods as well. In particular, at the culmination of the completion phase, he has developed the three bodies, or modes of existence, of a Buddha:

The dharma-body (dharmakaya) is the embodiment of his realization that all appearances-thoughts and phenomena are inherently devoid of any independent identity.

The enjoyment-body (sambhogakaya) is the means by which he communicates with yidam, his Master, other Buddhas and other advanced practitioners in meditation.

The emanation-body (nirmanakaya) appears in the world as though it were an ordinary physical body; but actually, this physical body is not compelled by the force of past action and afflictive mental states but rather by the force of will and previous supplication for the welfare of beings. The latter two together are termed the form-body, and the unity of all three the essential-body.

Adaptation from “Drinking the mountain stream, songs of Tibet’s beloved saint Milarepa”, Introduction: