Essentially, it is an evolution of consciousness represented by the appearance of progressively complex sentient bodies for the consciousness to express increasing levels of its potential, to culminate in a human form with immense potentials of thought, action, manipulation, invention, self-questioning, logic, reasoning, exploitation etc.
There are custodians in all religions who occupy positions of leadership who practice certain rituals based on the belief system and thereby set the foundation for rules of how life should be lived by the followers of the religion.
The words religion and spiritualism have ben used interchangeably by many. Though the two terms appear to mean similar, they are however different in perception and execution.