Bodhidharma was a Buddhist monk who lived during the 5th / 6th century. He is traditionally credited as the transmitter of Chan Buddhism to China. There was also this destiny reading/ personality profiling technique which was said to be developed by him.
The manual plotting is pretty straight forward. But, with the help of technology, things gotten much easier.
Making sense of it, we could apply similar analysis that of BAZI. The year pillar could represent external, outwards, society, social setting as to how a person will behave and interact (i.e. this is often what other feel of you when the first met you).
The month could represent career and workplace setting as to how a person is likely to behave as well as to his/ her friends and acquaintance. In the day pillar it relates to the family, kids, spouse, close friends and confidantes.
On the hour pillar relates to the inner level of thinking, the values he /she holds dear, the subconscious level as well as the personality gravitation into the golden years.