How to understand the supply curve

Value determines price, supply and demand affect price, and price will also affect supply and demand. Generally speaking, when the supply exceeds the demand, the price will fall, and when the demand exceeds the supply, the price will rise. When the price rises, the supply will increase and the demand will decrease; when the price falls, the supply will decrease and the demand will increase.

When the price of the substitute commodity of this commodity falls, the demand of the substitute commodity of this commodity rises, the demand of this commodity A falls, and the demand curve shifts to the left.

Finally, understanding A is wrong. Understand that b is that supply and demand affect prices, not that prices affect supply and demand.

In other words, the supply is considered from the manufacturer's side.