"Children" ( beginners, newly committed) to the mature. The newbies are thought to have declared their commitment by undergoing a baptism by immersion. The Way they embarked upon renounced materialism, encouraged vegetarianism, pledged to behave with lovingkindness and attend learning sessions and group celebrations. Candidates for the highest level may have undergone an experience such as the mystery religions (notably the eleuthran mystery) provided, a psychic/spiritual event. As one ancient commentator post-Eleuthra said, one would never again fear death. Day 1 of the Eleuthran consisted of swimming in the sea with piglets...compare Jesus's casting demons into pigs and their jumping into the sea...quite reminiscent. And Paul said he practiced a mystery and he used different terms to describe his followers' different spiritual levels. Jesus insisted Lazarus wasn't dead and, sho nuff, he wasn't...just all dressed up for his death. The naked youth may have been naked beneath his cape in preparation for his psychic/spiritual initiation.
There are lots of ideas from cannibalism to homosexuality bandied about to explain the original communities. I think it was a type of mystery religion. The huge difference from it and the others is that this one dictated an earthly lifestyle, how to live, in addition to teaching the spiritual God System.