What are all the levels of astral projection?

Will you make clear to us the system of progress in astral planes? 

A sleep and a forgetting is the first step. Your mother slept for a year. Same with brother, Will. Abe, also. The astral body requires about a year to adjust itself to this rarer, more mature environment. Mother thought I might sleep half a year―another, not at all. The rule is not an arbitrary one. You think I will not sleep? Those who told you know best. 

—Dorothy Wordsworth

Dorothy Wordsworth