The only institutional factor to this associated the Sangha, but lay Buddhists may well only interact with the Sangha by generating offerings to monks. For all Buddhists, lay and monastic, convertion to Buddhism involved accepting the "3 Refuges," , Tri-Sharaṇa, i.e. (1) Refuge in the Buddha, (2) Refuge in the Dharma, and (3) Refuge in the Sangha. Presumably a person should know about the Buddha to choose refuge in him, but this is presupposed.