The first teachings of the Buddha, which form the body of the Hinayana (or Small Vehicle of Buddhism), are based on the Four Noble Truths:
The first one recognizes the existence of suffering into the world in which we live. The second one shows the cause of this suffering, which is the ignorance that produces the clinging to an ego, the passions and the confusion that lead to actions (karma) the result of which is the suffering of samsara, the vicious circle of conditioned existence. The third truth states the existence of an end to the suffering and the forth one describes the path that leads to this end, the so-called Noble Eightfold Path.
The Noble Eightfold Path is divided into three sections: Śīla (which concerns wholesome physical actions), Samadhi (which concerns the meditative concentration of the mind) and Prajñā (which concerns spiritual insight into the true nature of all things).
Śīla is morality - abstaining from unwholesome deeds of body and speech. Within the division of sila are three parts of the Noble Eightfold Path:
Śīla is the foundation of Samadhi (meditative cultivation or mind cultivation).
Samadhi is developing mastery over one's own mind. Within this division are another three parts of the Noble Eightfold Path:
The primary means of cultivating samādhi is meditation in its two types of śamatha and vipaśyanā. Upon development of samādhi, one's mind becomes purified of defilement, calm, tranquil, and luminous and gives rise to Prajñā, the wisdom that understands the true nature of mind and phenomena.
Prajñā is the wisdom that purifies the mind. Within this division fall two more parts of the Noble Eightfold Path:
Prajñā is based on a realization of Dependent Origination, the Four Noble Truths and the Noble Eightfold Path, and is the wisdom that is able to extinguish afflictions and bring about, by its enlightenment, the nirvana, the release from all suffering.