What do the Heavenly Stems and Earthly Branches mean? Where do they originate? How are they divided?

The Heavenly Stems and Earthly Branches are a unique astronomical calendar created by ancient Chinese to record events. It originated from the ancient simple materialist dialectics thought of the unity of heaven, earth and man in our country. Ancient sages believed that Tao gave birth to one, one gave birth to two, two gave birth to three, and three gave birth to all things; Wuji gave birth to Tai Chi, Tai Chi gave birth to two rituals, two rituals gave birth to four images, four images gave birth to Bagua, and Bagua manifested all things. The nature of nature is strong and vigorous, the nature of earth is smooth and accommodating, the nature of heaven and earth generates people and generates itself. Therefore, human life must reflect the operation of heaven and earth. For this reason, the 24 solar terms were born, my country's unique lunisolar calendar was created, and my country's numerology (including eight-character prediction, Da Liu Ren, Qi Men Dun, Tian Di Kan Yu, numerology and Feng Shui, etc.) was formed. Therefore, the ancients used the heavenly stems and earthly branches to record events and make predictions. Specifically divided, the ten phases of the heavenly stems: A, B, Bing, Ding, Wuji, Geng, Xin, Rengui; the twelve earthly branches: Zichou Yinmao, Chensi, Wuwei, Shenyouxuhai. Heaven and earth match each other, and the way of heaven is its own. Therefore, the heavenly stems must be combined and arranged with the earthly branches in order to keep track of events.