Although a consecrated fire is the central element of every (havan) homa ritual, the procedure and items offered to the fire vary by what occasions the ceremony, or by the benefit expected from the ritual. Procedures invariably involve -
the kindling and consecration of the sacrificial fire;
the invocation of one or more divinities; and,
the making of offerings (whether real or visualized) to them with the fire as via media, amid the recitation of prescribed prayers and mantras.