What does the adjutant in fortune telling mean?

Adjutants are also called partial officials, the same sex is adjutant, the opposite sex is official, and their daily work represents themselves, which is called me for short.

Adjutant: If the sun is a nail, there is Geng Jin in the eight characters, and Geng Jin is A's adjutant.

Officer: If the sun is dry, there is something in the eight characters, and Xin is Jia's official. (A is Yang, Xin is Yin)