Linux and Unix screen command - options to start quickly

To begin, start screen by running  screen in the command line. the screen session will be created.
Ctrl a is the default modifier for screen. You'll prefix every command with it. 

• Then to detach the screen session press  Ctrl a  + d 
• to list the screen sessions screen -list 
• to reattach to a screen session type screen -r session-number-from-list e.g: screen -r 2531

For more options use screen --help.