Vim windows and buffers

  question, vim

Do not understand several states of buffer:

Hidden buffer, hidden buffer, is being edited but not displayed on the screen.

What kind of files are being edited but will not be displayed on the screen? Generally, when vim is used, if VIM is used:b1To switch the buffer displayed on the screen, and if the current buffer is not saved, you will be prompted to save and switch again. then this onehiddenHow did the state come out?

-(Inactive buffer, inactive buffer, not being edited)
 A (Active buffer, active buffer, currently displayed on the screen)
 H (Hidden buffer, hidden buffer, being edited but not displayed on the screen)
 % (current buffer, Current Buffer)
 # (Alternate buffeer, swap buffer)
 = (Readonly buffer, read-only buffer)
 +(Modified buffer, Changed Buffer)

How do you understand the above states?

There are several buffers under a window, but only one buffer can be displayed, so the rest is hidden