What is the real meaning of heavenly stems and earthly branches and the specific meaning of heavenly stems and earthly branches?

The true meaning of heavenly stems and earthly branches is as follows:

During the Spring and Autumn Period and the Warring States Period, people used the twelve earthly branches to record the moon. The Western Han Dynasty adopted the 12-day overtime system, and then recorded the year with official support. The fifth day of the Tang Dynasty replaced a thousand moons. In the Northern Song Dynasty, cadres and branches were used to cooperate with each other to observe discipline.

At this point, all the branches can be used for calendar year, calendar month and calendar day, which is the origin of the branch calendar Jiazi calendar. The trunk and branch timing method has been used in China ever since.