Sources of authority in Buddhism
Although Buddhists may stress the authority of individual experience, there are nevertheless other sources of authority in Buddhism as an institution (or institutions). The historical Buddha, and even more so his teaching, the Dharma/Dhamma, have the authority of his enlightenment experience and his full insight into the truth. This would also apply to in Mahayana to those sutras made known after the earthly life of the historical Buddha.
The sangha, or monastic community, was created not only for the spiritual development of individuals who joined, but also to preserve and transmit the teaching. Thus they have great authority in practice in many Buddhist contexts, particularly male monks. There were early schisms in the sangha and so there were several monastic lineages within the non-Mahayana forms of Buddhism. In some forms of Mahayana Buddhism, such as Tibetan Buddhism, the monastic sangha is very important, in other developments, especially in China and Japan, there can be married rather than monastic clergy and lay leadership. In some Buddhist groups, new forms of leadership have been developed, such as the Dharmachari in the Triratna organisation. The New Kadampa Tradition focuses on the books written by its founder. Although the term sangha tends to be restricted to monastics (and often, where the female ordination lines do not exist, male monks), the early texts talk of a fourfold sangha of monks, nuns, laymen and laywomen, so other Buddhists use the term for the whole Buddhist community.
Monks (and sometimes nuns or not-quite-nuns) can be involved in teaching children and young people in formal and informal educational settings. They may provide advice and counselling to lay people, as well as conducting ceremonies. Within the monastic traditions of Zen, the relationship between teacher and apprentice is crucial, as the truth cannot be put into words but only transmitted mind to mind. In Tibetan Buddhism, both monastic and lay Buddhists may take refuge in a particular lama (guru or teacher) who guides their spiritual progress. Some leading lamas (such as the Dalai Lama) are considered to be tulkus, reincarnations/rebirths of particular identified holy teachers as well as manifestations of a Buddha or bodhisattva.