What does it mean to decorate the wall with a yellow calendar?

"Decorate the wall" in the yellow calendar means to repair the low wall. Nowadays, it is more understood as the decoration or construction of buildings such as walls and yards.

Introduction to the yellow calendar:

According to legend, it was created by the Yellow Emperor, so it was called the Yellow Calendar. However, because the word "book" in Tongshu is homophonic with the word "lose", it is also called "Tong Sheng" because it is taboo. The Gregorian calendar is based on the lunar calendar in China, and many calendars show the good luck and bad luck of a day. The main contents of the Gregorian calendar are the date table of the 24 solar terms, the good and bad luck of each day, the fortune of the zodiac and so on.