Starting or re-entering an already running session (Works regardless of whether the session was detached properly or the internet connection went kaput)
screen -D -RR
If multiple users are going to share the same machine and all want to use screen, then use
screen -D -RR <screen-alias>
To start with screen will only have one screen.
To start a new screen keyboard shortcut is
To get the list of active screens
To switch to a screen
is the integer number of the screen that you wish to switch to.
To exit a screen
To detach from screen
(then again screen -D -RR to re attach)
To be able to scroll
Esc to go back to normal mode
To display the help
To end your screen session, kill(exit) each individual screen window.
Ctrl+A k will kill a window. Or
Ctrl+D will also work (generally also much faster)