A person can achieve nirvana (complete peace and happiness by eliminating their attachment to worldly possessions and following the Eightfold Path
Eightfold Path: Right views, Right resolve, Right speech, Right conduct, Right livelihood, Right effort, Right mindfulness, and Right Concentration.
Buddhism is based on the teachings of an Indian prince named Siddharta Gautama who lived around 500 BCE. According to Buddhist tradition, the sheltered young prince was shocked by the suffering he saw outside his palace walls, so he left his life of luxury to seek answers. Eventually he succeeded, becoming the Buddha--the "Enlightened One." He spent the remaining 45 years of his life teaching the dharma (the path to liberation from suffering) and establishing the sangha (a community of monks).
Mahayana Buddhism, which literally means "Great Vehicle" in sanskrit, is mainly the predominant sect in central and east Asia, and is making its appearance in western culture in forms of Tibetan, Zen, and Pure land Buddhism. The origin of Mahayana Buddhism is now traced to about the beginning of the common era. The Mahayana ideal is the bodhisattva, "one bearing enlightment" who realized it was important to save all others before realizing their own redemption. In this denomination, they early on acknowledged the pularity of Buddhas that could also act from outside this world. One of the main goals of Mahayana was to unfold or find the truth or hidden gem of enlightment. Mahayana has come to be known as the second turning of the Wheel of Dharma.
Theravada Buddhism, also known as Southren Buddhism, is mainly in South and South East Asia. It is the only surviving tradition of the 30 original sects and is said to be the closest to the original teachings of the Buddha. Their focal point is to an order of monks. Their ideal is to a person's nonattachment to the world and practicing the Buddhist path of renunciation. The monks main task is to live to that ideal to pass on Buddhist teachings and way of life. Theravada is also known as the first turning of the Wheel of Dharma.
Vajrayana Buddhism is the most exotic of the denominations and is the third turning of the Wheel of Dharma. Around the 3rd century in the common era, Vajrayana became the more prominent denomination in India and many other regions of the Buddhist world. It dominated in the Himalayan region and quite a few other areas. Vajrayana is the "secret vehicle" of Buddhism, and is also called the diamond or electric vehicle, due to its indestructable and clarity qualities, or in reference to the thunderbolt scepter of Indra, a Vedic god. The vajra represents cosmic power and its prongs represent different Buddhas, and the power of enlightment itself. Vajrayana uses aspects of both Buddhism and Hinduism and uses mantras, which are magical chants and syllables, a lot. It is also known as Mantrayana because of that. Tantric Buddhism is another name it is known as due to the great use of Tantric texts and rites.