What knowledge do you need to learn calligraphy?

About my knowledge of calligraphy, if compared to a mountain, its mountain is not high and the ground has no aura; Compared with a pool of water, the tan is not deep and the water is not clear enough; Calligraphy is not refined and famous. Later, when my knowledge and calligraphy were deep enough, I became alert and paid attention to the "concealment" and "truth" of calligraphy to prevent my calligraphy style from being destroyed. In recent years, I am almost 40 years old, and my ignorance and confusion about calligraphy have gradually decreased. Now I have surpassed the past for calligraphy. I don't know where I learned the strange words in books, and I often don't know how to write them. Yesterday, I saw a letter from "Xie Xie" asking about calligraphy, and learned that the truth of calligraphy is indeed like this. I think this is very good.