What do the different ways of commanding flags in ancient times mean?

There are many ways to command the flag, such as trees, dots, grinding and suppression. As mentioned above, Dashu asked the corresponding troops to stand by at any time and wait for orders; Point refers to the flag shaking in a certain direction, requiring the corresponding troops to advance or attack in that direction; Grinding refers to waving flags in a rotating way, asking the corresponding troops to change direction and turn around; Suppression, that is, lowering the flag, requires the corresponding troops to enter a hidden state.