What does it mean to stick a yellow note at the entrance of the building?
This should be a local custom. In some places, there is yellow paper on the stove in the kitchen. The way of offering sacrifices is to write "Kitchen God" on the corner of each stove with yellow paper, or buy a portrait with "Kitchen God" printed on it. Then burn incense and worship the kitchen god on the first and fifteenth day of each month, and give a column of incense to the kitchen god at weddings and funerals. Usually, family members should avoid the kitchen god when quarreling and fighting. Then on the 23rd of the twelfth lunar month, send it to Kitchen God. Sacrifice with caramel and rice cakes, or sprinkle sugar around the mouth of the kitchen god. Shut the kitchen god up and tell him not to speak ill of him.