Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
Top left: mission control (to see all desktops and drag a window to a different desktop)
Top right: notification centre
Bottom left: application windows
Bottom right: desktop
 
Top right - display sleep
Bottom right - desktop
Top left - mission control

Now that the power button on my Air locks the screen (came with one of the Big Sur betas - forget which) I removed bottom left.
Does your power button still lock the screen? Mine stopped working after I updated to 11.1
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.